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Astronomers Ponder The Role Of Physics In Life

September 25, 2017 by  
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Understanding the origin of life is arguably one of the most compelling quests for humanity. This quest has inevitably moved beyond the puzzle of life on Earth to whether there’s life elsewhere in the universe. Is life on Earth a fluke? Or is life as natural as the universal laws of physics?

Jeremy England, a biophysicist at the Massachusetts Institute of Technology, is trying to answer these profound questions. In 2013, he formulated a hypothesis that physics may spontaneously trigger chemicals to organize themselves in ways that seed “life-like” qualities.

Now, new research by England and a colleague suggests that physics may naturally produce self-replicating chemical reactions, one of the first steps toward creating life from inanimate substances.

This might be interpreted as life originating directly from the fundamental laws of nature, thereby removing luck from the equation. But that would be jumping the gun.

Life had to have come from something; there wasn’t always biology. Biology is born from the raw and lifeless chemical components that somehow organized themselves into prebiotic compounds, created the building blocks of life, formed basic microbes and then eventually evolved into the spectacular array of creatures that exist on our planet today.  

“Abiogenesis” is when something nonbiological turns into something biological and England thinks thermodynamics might provide the framework that drives life-like behavior in otherwise lifeless chemicals. However, this research doesn’t bridge life-like qualities of a physical system with the biological processes themselves, England said.

“I would not say I have done anything to investigate the ‘origin of life’ per se,” England told Live Science. “I think what’s interesting to me is the proof of principle – what are the physical requirements for the emergence of life-like behaviors?”

Self-organization in physical systems

When energy is applied to a system, the laws of physics dictate how that energy dissipates. If an external heat source is applied to that system, it will dissipate and reach thermal equilibrium with its surroundings, like a cooling cup of coffee left on a desk. Entropy, or the amount of disorder in the system, will increase as heat dissipates. But some physical systems may be  sufficiently out of equilibrium that they “self-organize” to make best use of an external energy source, triggering interesting self-sustaining chemical reactions that prevent the system from reaching thermodynamic equilibrium and thus maintaining an out-of-equilibrium state, England speculates. (It’s as if that cup of coffee spontaneously produces a chemical reaction that sustains a hotspot in the center of the fluid, preventing the coffee from cooling to an equilibrium state.) He calls this situation “dissipation-driven adaptation” and this mechanism is what drives life-like qualities in England’s otherwise lifeless physical system.

A key life-like behavior is self-replication, or (from a biological viewpoint) reproduction. This is the basis for all life: It starts simple, replicates, becomes more complex and replicates again. It just so happens that self-replication is also a very efficient way of dissipating heat and increasing entropy in that system.

In a study published July 18 in the journal Proceedings of the National Academy of Sciences,  England and co-author Jordan Horowitz tested their hypothesis. They carried out computer simulations on a closed system (or a system that doesn’t exchange heat or matter with its surroundings) containing a “soup” of 25 chemicals. Although their setup is very simple, a similar type of soup may have pooled on the surface of a primordial and lifeless Earth. If, say, these chemicals are concentrated and heated by an external source – a hydrothermal vent, for example – the pool of chemicals would need to dissipate that heat in accordance with the second law of thermodynamics. Heat must dissipate and the entropy of the system will inevitably increase.

Under certain initial conditions, he found that these chemicals may optimize the energy applied to the system by self-organizing and undergoing intense reactions to self-replicate. The chemicals fine-tuned themselves naturally. These reactions generate heat that obeys the second law of thermodynamics; entropy will always increase in the system and the chemicals would self-organize and exhibit the life-like behavior of self-replication.

“Essentially, the system tries a bunch of things on a small scale, and once one of them starts experiencing positive feedback, it does not take that long for it to take over the character of organization in the system,” England told Live Science.

This is a very simple model of what goes on in biology: chemical energy is burned in cells that are – by their nature – out of equilibrium, driving the metabolic processes that maintain life. But, as England admits, there’s a big difference between finding life-like qualities in a virtual chemical soup and life itself.

Sara Imari Walker, a theoretical physicist and astrobiologist at Arizona State University who was not involved in the current research, agrees.

“There’s a two-way bridge that needs to be crossed to try to bridge biology and physics; one is to understand how you get life-like qualities from simple physical systems and the other is to understand how physics can give rise to life,” Imari Walker told Live Science. “You need to do both to really understand what properties are unique to life and what properties are characteristic of things that you consider to be almost alive […] like a prebiotic system.”

Emergence of life beyond Earth?

Before we can even begin to answer the big question of whether these simple physical systems may influence the emergence of life elsewhere in the universe, it would be better to understand where these systems exist on Earth first.

“If, when you say ‘life,’ you mean stuff that is as stunningly impressive as a bacterium or anything else with polymerases and DNA, my work doesn’t yet tell us anything about how easy or difficult it is to make something that complex, so I shouldn’t speculate about what we’d be likely to find elsewhere than Earth,”  England said. (Polymerases are proteins that assemble DNA and RNA.)

This research doesn’t specifically identify how biology emerges from nonbiological systems, only that in some complex chemical situations, surprising self-organization occurs. These simulations do not consider other life-like qualities – such as adaptation to environment or reaction to stimuli. Also, this thermodynamics test on a closed system does not consider the role of information reproduction in life’s origins, said Michael Lässig, a statistical physicist and quantitative biologist at the University of Cologne in Germany.

“[This] work is indeed a fascinating result on non-equilibrium chemical networks but it is still a long way from a physics explanation of the origins of life, which requires the reproduction of information,” Lässig, who was not involved in the research, told Live Science.

There’s a critical role for information in living systems, added Imari Walker. Just because there appears to be natural self-organization exhibited by a soup of chemicals, it doesn’t necessarily mean living organization.

“I think there’s a lot of intermediate stages that we have to get through to go from simple ordering to having a full-on information processing architecture like a living cell, which requires something like memory and hereditary,” said Imari Walker. “We can clearly get order in physics and non-equilibrium systems, but that doesn’t necessarily make it life.”

To say England’s work could be the “smoking gun” for the origin of life is premature, and there are many other hypotheses as to how life may have emerged from nothing, experts said. But it is a fascinating insight into how physical systems may self-organize in nature. Now that researchers have a general idea about how this thermodynamic system behaves, it would be a nice next step to identify sufficiently out-of-equilibrium physical systems that naturally occur on Earth, England said.


Astronomers Find Titanium Oxide On Aline Planet

September 22, 2017 by  
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For the first time ever, titanium oxide has been spotted in an exoplanet’s skies, a new study reports.

Astronomers using the European Southern Observatory’s Very Large Telescope (VLT) in Chile detected the substance in the atmosphere of WASP-19b, a huge, scorching-hot planet located 815 light-years from Earth.

The presence of titanium oxide in the atmosphere of WASP-19b can have substantial effects on the atmospheric temperature structure and circulation,” study co-author Ryan MacDonald, an astronomer at the University of Cambridge in England, said in a statement.  

One possible effect is “thermal inversion.” If enough titanium oxide is present, the stuff can keep heat from entering or exiting an atmosphere, causing upper layers to be hotter than lower layers, researchers said. (This phenomenon occurs in Earth’s stratosphere, but the culprit is ozone, not titanium oxide.)

Artist’s illustration showing the exoplanet WASP-19b, whose atmosphere contains titanium oxide. In large enough quantities, titanium oxide can prevent heat from entering or escaping an atmosphere, leading to a “thermal inversion” in which temperatures are higher in the upper atmosphere than lower down.

WASP-19b is a bizarre world about the mass of Jupiter. The alien planet lies incredibly close to its host star, completing one orbit every 19 hours. As a result, WASP-19b’s atmospheric temperatures are thought to hover around 3,600 degrees Fahrenheit (2,000 degrees Celsius).

The research team — led by Elyar Sedaghati of the European Southern Observatory, the German Aerospace Center and the Technical University of Berlin — studied WASP-19b for more than a year using the VLT’s refurbished FORS2 instrument. These observations allowed them to determine that small amounts of titanium oxide, along with water and wisps of sodium, swirl around in the exoplanet’s blistering air.

“Detecting such molecules is, however, no simple feat,” Sedaghati said in the same statement. “Not only do we need data of exceptional quality, but we also need to perform a sophisticated analysis. We used an algorithm that explores many millions of spectra spanning a wide range of chemical compositions, temperatures, and cloud or haze properties in order to draw our conclusions.”

In addition to shedding new light on WASP-19b, the new study — which was published online today (Sept. 13) in the journal Nature — should improve researchers’ modeling of exoplanet atmospheres in general, team members said.

“To be able to examine exoplanets at this level of detail is promising and very exciting,” said co-author Nikku Madhusudhan, also of the University of Cambridge. 


With Boron On Mars Prove Life Once Existed

September 21, 2017 by  
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NASA’s Mars rover Curiosity has discovered boron in Gale Crater — new evidence that the Red Planet may have been able to support life on its surface in the ancient past.

Boron is a very interesting element to astrologists; on Earth, it’s thought to stabilize the sugary molecule ribose. Ribose is a key component of ribonucleic acid (RNA), a molecule that’s present in all living cells and drives metabolic processes. But ribose is notoriously unstable, and to form RNA, it is thought that boron is required to stabilize it. When dissolved in water, boron becomes borate, which, in turn, reacts with ribose, making RNA possible.

In a new study published in the journal Geophysical Research Letters, researchers analyzed data gathered by Curiosity’s ChemCam (Chemistry and Camera) instrument, which zaps rocks with a powerful laser to see what minerals they contain. ChemCam detected the chemical fingerprint of boron in calcium-sulfate mineral veins that have been found zigzagging their way through bedrock in Gale Crater, the 96-mile-wide (154 kilometers) crater that the rover is exploring. These veins were formed by the presence of ancient groundwater, meaning the water contained borate.

The find raises exciting possibilities, the researchers said.

“Because borates may play an important role in making RNA — one of the building blocks of life — finding boron on Mars further opens the possibility that life could have once arisen on the planet,” study lead author Patrick Gasda, a postdoctoral researcher at Los Alamos National Laboratory in New Mexico, said in a statement. 

“Borates are one possible bridge from simple organic molecules to RNA,” he added. “Without RNA, you have no life. The presence of boron tells us that, if organics were present on Mars, these chemical reactions could have occurred.”

Scientists have long hypothesized that the earliest “proto-life” on Earth emerged from an “RNA World,” where individual RNA strands containing genetic information had the ability to copy themselves. The replication of information is one of the key requirements for basic lifelike systems. Therefore, the detection of boron on Mars, locked in calcium-sulfate veins that we know were deposited by ancient water, shows that borates were present in water “0 to 60 degrees Celsius (32 to 140 degrees Fahrenheit) and with neutral-to-alkaline pH,” the researchers said.

“We detected borates in a crater on Mars that’s 3.8 billion years old, younger than the likely formation of life on Earth,” Gasda added. “Essentially, this tells us that the conditions from which life could have potentially grown may have existed on ancient Mars, independent from Earth.”

Since landing on Mars in 2012, Curiosity has uncovered compelling evidence that the planet used to be a far wetter place than it is now. For example, the rover has found evidence of a lake-and-stream system inside Gale Crater that lasted for long stretches in the distant past. And, by climbing the slopes of Mount Sharp — the 3.4-mile-high (5.5 km) mountain in the crater’s center — Curiosity has been able to examine various layers of sedimentary minerals that formed in the presence of ancient water. 

These studies are helping scientists gain a better understanding of how long these minerals were dissolved in the water, where they were deposited and, ultimately, how they impacted the habitability of the Red Planet. The detection of boron is another strand of evidence supporting the idea that ancient life might have existed on our neighboring planet.


Cassini Captures On Saturn’s Rings

September 19, 2017 by  
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NASA’s Cassini spacecraft has captured a spectacular photo of a perplexing wave structure in one of Saturn’s rings as the probe heads into its final days at the gas giant. 

The rings of Saturn are embedded with billions of water-ice particles ranging in size from grains of sand to monstrous chunks. Saturn’s rings also feature waves that propagate outward in spiral patterns. 

The new image from Cassini captures an up-close view of a spiral density wave visible in Saturn’s B ring. The wave structure is a buildup of material that has formed from the gravitational pull of Saturn’s moons, NASA officials said.

The density wave visible in Saturn’s B ring originates 59,796 miles (96,233 kilometers) from the planet, where the “ring particles orbit Saturn twice for every time the moon Janus orbits

In the new image, the wave structure — aptly named the Janus 2:1 spiral density wave — appears to ricochet outward, away from Saturn and toward the upper-left corner of the photo, creating hundreds of bright wave crests. 

The density wave is generated by the gravitational pull of Saturn’s moon Janus. However, Janus and one of Saturn’s other moons, Epimetheus, share practically the same orbit and swap places every four years, creating a new crest in the wave, according to the statement. 

As a result, the distance between any pair of crests corresponds to four years’ worth of wave oscillations. This pattern represents the orbital history of Janus and Epimetheus, much like the rings of a tree reveal information about its growth. 

Based on this idea, the crests of the wave at the very upper left of the new Cassini image correspond to the positions of Janus and Epimetheus during the Saturn flybys of NASA’s twin Voyager probes in 1980 and 1981, according to the statement.

The recent images of Saturn’s B ring were taken on June 4, 2017, using Cassini’s narrow-angle camera. After 20 historic years in space, the Cassini mission will come to a close on Sept. 15, when the spacecraft will intentionally dive into Saturn’s atmosphere. 



Can The James Webb Telescope Find Life In Our Solar System

September 18, 2017 by  
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The soon-to-launch James Webb Space Telescope will turn its powerful eye on two of the solar system’s top candidates for hosting alien life: the icy moons Enceladus and Europa, the agency confirmed in a statement this month.

Both Europa (a moon of Jupiter) and Enceladus (a moon of Saturn) are thought to possess subsurface oceans of liquid water beneath thick outer layers of ice. Both moons have also shown evidence of enormous plumes of liquid shooting up through cracks in the surface ice; these plumes could be caused by subsurface geysers, which could provide a source of heat and nutrients to life-forms there, scientists have said.

“We chose these two moons because of their potential to exhibit chemical signatures of astrobiological interest,” said Heidi Hammel, executive vice president of the Association of Universities for Research in Astronomy (AURA), who is leading an effort to use the telescope to study objects in Earth’s solar system.  

The James Webb Space Telescope, nicknamed “Webb,” will capture infrared light, which can be used to identify objects that generate heat but are not hot enough to radiate light (including humans, which is why many night-vision systems utilize infrared light). Researchers are hoping that Webb can help to identify regions on the surfaces of these moons where geologic activity, such as plume eruptions, are taking place. 

Enceladus’ plumes were studied in detail by the Cassini probe at Saturn. The spacecraft spotted hundreds of plumes, and even flew through some of them and sampled their composition. Europa’s plumes were spotted by the Hubble Space Telescope, and researchers know far less about them than those on Europa.

“Are they made of water ice? Is hot water vapor being released? What is the temperature of the active regions and the emitted water?” Geronimo Villanueva, lead scientist on the Webbobservation of Europa and Enceladus, said in the statement. “Webb telescope’s measurements will allow us to address these questions with unprecedented accuracy and precision.”

Webb’s observations will help pave the way for the Europa Clipper mission, a $2 billion orbital mission to the icy moon. Scheduled to launch in the 2020s, Europa Clipper will search for signs of life on Europa. The observations with Webb could identify areas of interest for the Europa Clipper mission to investigate, according to the statement.

As seen by Webb, the Saturn moon Enceladus will appear about 10 times smaller than Europa, so scientists will not be able to capture high-resolution views of Enceladus’ surface, according to the statement. However, Webb can still analyze the molecular composition of Enceladus’ plumes. 

But it’s also possible that the observations won’t catch a plume erupting from Europa’s surface; scientists don’t know how frequently these geysers erupt, and the limited observing time with Webb may not coincide with one of them. The telescope can detect organics — elements such as carbon that are essential to the formation of life as we know it — in the plumes. However, Villanueva cautioned that Webb does not have the power to directly detect life-forms in the plumes.

Webb is set to launch in 2018 and will orbit the sun at the L2 Lagrange point, which is about one million miles (1.7 million km) farther from the sun than the Earth’s orbit around the sun. The telescope will provide high-resolution views of both the very distant and very nearby universe. Scientists have already begun submitting ideas for objects or regions that should be observed using Webb’s powerful eye, and Europa and Enceladus are among the objects that are now guaranteed observing time.


Project Blue Telescope Goes CrowdFunding

September 15, 2017 by  
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The private space telescope initiative Project Blue launched a new crowdfunding campaign Sept. 6 in a second attempt to raise money for its mission to directly image Earth-like exoplanets. 

The initiative aims to launch a small space telescope into low-Earth orbit. The telescope will spy on our interstellar neighbor Alpha Centauri and image any Earth-like planets that might orbit the star system.

In support of Project Blue, BoldlyGo Institute and numerous organizations, including the SETI (Search for Extraterrestrial Intelligence) Institute, the University of Massachusetts Lowell and Mission Centaur, launched an IndieGoGo campaign to raise $175,000 over the next two months. The funds will be used to establish mission requirements, design the initial system architecture and test its capability for detecting exoplanets. Project leaders will also begin looking for potential partners who could manufacture parts of the space telescope, representatives said in a statement. 

“We’re very excited to pursue such an impactful space mission and, as a privately-funded effort, to include a global community of explorers and space science advocates in Project Blue from the beginning,” Jon Morse, CEO of BoldlyGo Institute, said in the statement.

Last year, Project Blue organizers attempted to raise $1 million through the crowdfunding platform Kickstarter, but the campaign was canceled after only $335,597 was contributed and Project Blue received none of the funds (as is Kickstarter’s policy). 

With the IndieGoGo campaign, however, the organizers have a more flexible goal and will be able to keep all contributions from supporters, even if the initial goal of $175,000 is not reached. So far, more than $45,000 has been raised through the campaign.

The neighboring star system Alpha Centauri is located only 4.37 light-years from Earth, making it a target for scientific research. Project Blue estimates it will take about $50 million to build the special-purpose telescope, which is planned to launch in 2021. 

The small space telescope will use a specialized coronagraph to block the bright glare of Alpha Centauri’s stars and detect planets that may be orbiting there. One planet, Proxima b, has already been detected around Proxima Centauri. 

However, Proxima b was discovered indirectly, by measuring the planet’s gravitational effect on its host star. Instead, the Project Blue telescope will be designed to directly image Earth-like planets in Alpha Centauri’s neighborhood.



Do Trappist-1 Planets Have Enough Water For Alien Life

September 11, 2017 by  
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The new study looks at how much ultraviolet (UV) radiation is received by each of the planets, because this could affect how much water the worlds could sustain over billions of years, according to the study. Lower-energy UV light can break apart water molecules into hydrogen and oxygen atoms on a planet’s surface, while higher-energy UV light (along with X-rays from the star) can heat a planet’s upper atmosphere and free the separated hydrogen and oxygen atoms into space, according to the study. (It’s also possible that the star’s radiation destroyed the planets’ atmospheres long ago.)

The researchers measured the amount of UV radiation bathing the TRAPPIST-1 planets using NASA’s Hubble Space Telescope, and in their paper they estimate just how much water each of the worlds could have lost in the 8 billion years since the system formed.

It’s possible that the six innermost planets (identified by the letters b, c, d, e, f and g), pelted with the highest levels of UV radiation, could have lost up to 20 Earth-oceans’ worth of water, according to the paper. But it’s also possible that the outermost four planets (e, f, g and h — the first three of which are in the star’s habitable zone) lost less than three Earth-oceans’ worth of water.

If the planets had little or no water to start with, the destruction of water molecules by UV radiation could spell the end of the planets’ habitability. But it’s possible that the planets were initially so rich in liquid water that, even with the water loss caused by UV radiation, they haven’t dried up,  according to one of the study’s authors, Michaël Gillon, an astronomer at the University of Liège in Belgium. Gillon was also lead author on two studies that first identified the seven TRAPPIST-1 planets.

“It is very likely that the planets formed much farther away from the star [than they are now] and migrated inwards during the first 10 million years of the system,” Gillon told in an email.

Farther away from their parent star, the planets might have formed in an environment rich in water ice, meaning the planets could have initially had very water-rich compositions.

“We’re talking about dozens, and maybe even hundreds of Earth-oceans, so a loss of 20 Earth-oceans wouldn’t matter much,” Gillon said. “What our results show is that even if the outer planets were initially quite water-poor like the original Earth, they could still have some water on their surfaces.”


NASA Researching The Stripes On Venus

September 8, 2017 by  
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A proposed NASA mission could solve the mystery of how Venus got its stripes.  

To the human eye, the cloud tops of Venus may look smooth and monochrome, but in ultraviolet light, dark and light streaks decorate Earth’s sister planet. The cause of these stripes is unknown, and Venus’ thick, blistering atmosphere (which is hot enough to melt lead) has made the world a difficult planet to study.

Now, NASA has invested money in a proposed mission that could help researchers figure out what causes the Venusian bands, according to a statement from the agency. The mission would use a very small space probe, equipped with cutting-edge technology, the statement said. 

The CubeSat UV Experiment, or CUVE, would orbit Venus over the poles and study the planet’s atmosphere in ultraviolet and visible wavelengths of light. Venus’ cloud tops scatter visible light, which makes the planet look like a smooth, featureless globe. But some of the material in the clouds absorbs ultraviolet light, creating the dark stripes, according to the statement. 

“The exact nature of the cloud-top absorber has not been established,” Valeria Cottini, CUVE principal investigator and a researcher at the University of Maryland, said in the statement. “This is one of the unanswered questions, and it’s an important one.”

One hypothesis that could explain how Venus gets its stripes posits that material from
“deep within Venus’ thick cloud cover” could rise into the cloud tops via convection (in which hot material in a fluid naturally rises above cold material). Winds would then disperse the material along breezy pathways, creating streaks. 

The CUVE team has now received additional funding from NASA’s Planetary Science Deep Space SmallSat Studies, or PSDS3, to further develop the mission concept. 

The spacecraft would be a cubesat, or a miniature satellite that typically consists of single unites that are about 10 inches (25.4 centimeters) cubed. CUVE would include a miniaturized ultraviolet camera “to add contextual information and capture the contrast features,” according to the statement, and a spectrometer to study the UV and visible light in detail.  

CUVE could also carry a “lightweight telescope equipped with a mirror made of carbon nanotubes in an epoxy resin,” officials said in the statement. “To date, no one has been able to make a mirror using this resin.” 

Planet Venus is often likened to Earth but with a runaway greenhouse problem. The 2nd planet from the sun is hot shrouded with deadly clouds. Those are hints. Now test your knowledge of Venus facts.

The nanotubes and epoxy would be poured into a mold, heated to harden the epoxy and then coated with a reflective material. This telescope would be lightweight and easy to reproduce, and would not require polishing, which is typically time-consuming and expensive, according to the statement.

“This is a highly focused mission — perfect for a cubesat application,” Cottini said in the statement. She later added, “CUVE would complement past, current and future Venus missions and provide great science return at lower cost.”


The Voyage Of Cassini-Huygens

August 29, 2017 by  
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The Cassini spacecraft has been orbiting Saturn since 2004. The mission is known for discoveries such as finding jets of water erupting from Enceladus, and tracking down a few new moons for Saturn. Now low on fuel, the spacecraft will make a suicidal plunge into the ringed planet in 2017 and capture some data about Saturn’s interior on the way. (This will avoid the possibility of Cassini crashing someday onto a potentially habitable icy moon, such as Enceladus or Rhea.)

The ambitious mission is a joint project among several space agencies, which is a contrast from the large NASA probes of the past such as Pioneer and Voyager. In this case, the main participants are NASA, the European Space Agency and Agenzia Spaziale Italiana (the Italian space agency).

Cassini is the first dedicated spacecraft to look at Saturn and its system. It was named for Giovanni Cassini, a 17th-century astronomer who was the first to observe four of Saturn’s moons — Iapetus (1671), Rhea (1672), Tethys (1684) and Dione (1684). 

Before this spacecraft came several flybys of Saturn by Pioneer 11 (1979), Voyager 1 (1980) and Voyager 2 (1981). Some of the discoveries that came out of these missions included finding out that Titan’s surface can’t be seen in visible wavelengths (due to its thick atmosphere), and spotting several rings of Saturn that were not visible with ground-based telescopes.

It was shortly after the last flyby, in 1982, that scientific committees in both the United States and Europe formed a working group to discuss possible future collaborations. The group suggested a flagship mission that would orbit Saturn, and would send an atmospheric probe into Titan. However, there was a difficult “fiscal climate” in the early 1980s, NASA’s Jet Propulsion Laboratory noted in a brief history of the mission, which pushed approval of Cassini to 1989.

The Europeans and the Americans each considered either working together, or working solo. A 1987 report by former astronaut Sally Ride, for example, advocated for a solo mission to Saturn. Called “NASA’s Leadership and America’s Future in Space,” the report said that studying the outer gas giant planets (such as Saturn) help scientists learn about their atmospheres and internal structure. (Today, we also know that this kind of study helps us predict the structure of exoplanets, but the first exoplanets were not discovered until the early 1990s.) 

“Titan is an especially interesting target for exploration because the organic chemistry now taking place there provides the only planetary-scale laboratory for studying processes that may have been important in the prebiotic terrestrial atmosphere,” the report added, meaning that on Titan is chemistry that could have been similar to what was present on Earth before life arose.

Cassini’s development came with at least two major challenges to proceeding. By 1993 and 1994, the mission had a $3.3 billion price tag (roughly $5 billion in 2017 dollars, or about half the cost of the James Webb Space Telescope.) Some critics perceived this as overly high for the mission. In response, NASA pointed out that the European Space Agency was also contributing funds, and added that the technologies from Cassini were helping to fund lower-cost NASA missions such as the Mars Global Surveyor, Mars Pathfinder and the Spitzer Space Telescope, according to JPL. 

Cassini also received flak from environmental groups who were concerned that when the spacecraft flew by Earth, its radioisotope thermoelectric generator (nuclear power) could pose a threat to our planet, JPL added. These groups filed a legal challenge in Hawaii shortly before launch in 1997, but the challenge was rejected by the federal district court in Hawaii and the Ninth Circuit Court of Appeals.

To address concerns about the spacecraft’s radioisotope thermoelectric generators, which are commonly used for NASA missions, NASA responded by issuing a supplementary document about the flyby and detailing the agency’s methodology for protecting the planet, saying there was less than a one-in-a-million chance of an impact occurring.

Cassini didn’t head straight to Saturn. Rather, its mission involved complicated orbital mechanics. It went past several planets — including Venus (twice), Earth and Jupiter — to get a speed boost by taking advantage of each planet’s gravity.

The nearly 12,600-lb. (about 5,700 kilograms) spacecraft was hefted off Earth on Oct. 15, 1997. It went by Venus in April 1998 and June 1999, Earth in August 1999 and Jupiter in December 2000.

Cassini settled into orbit around Saturn on July 1, 2004. Among its prime objectives were to look for more moons, to figure out what caused Saturn’s rings and the colors in the rings, and understanding more about the planet’s moons.

Perhaps Cassini’s most detailed look came after releasing the Huygens lander toward Titan, Saturn’s largest moon. The lander was named for Dutch scientist Christiaan Huygens, who in 1654 turned a telescope toward Saturn and observed that its odd blob-like shape — Galileo Galilei had first seen the shape in a telescope and drew it in his notebook as something like ears on the planet — was in fact caused by rings. 

The Huygens lander descended through the mysterious haze surrounding the moon and landed on Jan. 14, 2005. It beamed information back to Earth for nearly 2.5 hours during its descent, and then continued to relay what it was seeing from the surface for 1 hour 12 minutes.

In that brief window of time, researchers saw pictures of a rock field and got information back about the moon’s wind and gases on the atmosphere and the surface.

One of the defining features of Saturn is its number of moons. Excluding the trillions of tons of little rocks that make up its rings, Saturn has 62 discovered moons as of September 2012. NASA lists 53 named moons on one of its websites.

In fact, Cassini discovered two new moons almost immediately after arriving (Methone and Pallene) and before 2004 had ended, it detected Polydeuces.

As the probe wandered past Saturn’s moons, the findings it brought back to Earth revealed new things about their environments and appearances. Some of the more notable findings include:

Saturn has not gone ignored, either. For example, in 2012, a NASA study postulated that Saturn’s jet streams in the atmosphere may be powered by internal heat, instead of energy from the sun. Scientists believe that heat brings up water vapor from the inside of the planet, which condenses as it rises and produces heat. That heat is believed to be behind jet stream formation, as well as that of storms.

Mission extension and end

Cassini was originally slated to last four years at Saturn, until 2008, but its mission has been extended multiple times. Its last and final leg was called the Cassini Solstice Mission, named because the planet and its moons reached the solstice again toward the mission end. Saturn orbits the sun every 29 Earth-years. With Cassini’s mission lasting 13 years, this meant that the spacecraft observed almost half of Saturn’s seasonal change as the planet went around its orbit.

In 2016, the spacecraft was set on a series of final maneuvers to provide close-up views of the rings, with the ultimate goal of plunging Cassini into Saturn on Sept. 15, 2017. This protected Enceladus and other potentially habitable moons from the (small) chance of Cassini colliding with the surface, spreading Earth microbe.

Major milestones of the finale included:

Ring-grazing orbits: Every week between Nov. 30, 2016, and April 22, 2017, Cassini did loops around Saturn’s poles to look at the outer edge of the rings, to learn more about their particles, gases and structure. It also observed small moons in this region, including Atlas, Daphnis, Pan and Pandora.

On April 22, 2017, Cassini made the final flyby of Titan. The flyby was done in such a way to change Cassini’s orbit so that it began 22 dives (once a week) between the planet and its rings. This was the first time any spacecraft explored this zone, and it entailed some risk because the orbit brought it between the outer part of the atmosphere and the inner zone of the rings (where it is at risk of striking particles or gas molecules). 

On Sept. 15, 2017, Cassini will make a suicidal plunge into Saturn, taking measurements for as long as its instruments can make communications back to Earth.

Some of the science Cassini performed during this period included creating maps of the planet’s gravity and magnetic fields, estimating how much material is in the rings, and taking high-resolution images of Saturn and its rings from close-up. 

The spacecraft made an interesting discovery from its new vantage point. It found that Saturn’s magnetic field is closely aligned with the planet’s axis of rotation, which baffled scientists because of how they think magnetic fields are generated — through a difference of tilt between the magnetic field and a planet’s rotation. As of late July 2017, however, scientists planned to gather more data to see if perhaps Saturn’s internal processes confused their measurements.




Will The James Webb Telescope Easily Find Earth Like Planets

August 17, 2017 by  
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The James Webb Space Telescope (JWST), billed as “NASA’s premier observatory of the next decade,” could search for signs of an atmosphere on Proxima b. When it launches next year, JWST will be the most powerful space-based observatory yet, and the largest ever contrcuted. Its 6.5-meter mirror (nearly three times the size of the Hubble Space Telescope’s mirror) is expected to yield insights into the entire universe, ranging from the formation of planets and galaxies to peering at exoplanets in higher resolution than ever before.

There is only so much telescope time for JWST, however, and as with Hubble observations, astronomers will receive access on a competitive basis. Among the many proposals for the telescope that have emerged in recent months following NASA’s solicitation of science projects, a paper accepted for publication in the Astrophysical Journal (a draft version of which is available on Arxiv) suggests using the JWST to probe Proxima b’s atmosphere.

If such observations go forward, the telescope will provide an unparalleled view of Proxima b. JWST is optimized for infrared wavelengths, which can be used to examine a planet’s heat emissions. Because JWST will be orbiting the sun, it won’t be peering through Earth’s atmosphere, whose warmth can interfere with observations.

“Other telescopes are not able to do this,” Ignas Snellan, an astronomy researcher at the University of Leiden in the Netherlands and the paper’s lead author, told Seeker in an email. “Hubble is too small and works in the wrong wavelength range. Current ground-based telescopes cannot touch the mid-infrared because of very high thermal backgrounds, and are in a not enough stable environment, in contrast to JWST, which operates from space.”

The astronomers hope to use JWST to determine whether or not Proxima b has an atmosphere. Snellan said this will be very difficult, because the planet is very faint compared to its parent star. The research team therefore proposes looking for carbon dioxide.

The team’s method “looks for a striking signature that is expected from this molecule at 15 micron, that varies strongly from one wavelength to the next,” Snellan explained. “It will be very challenging, but we think doable.”

Finding carbon dioxide isn’t necessarily a sign of life as we know it. The gas is only found in trace amounts in Earth’s atmosphere (which is mostly made up of nitrogen and oxygen), even though carbon is the primary basis for life on our planet.

But carbon dioxide is a common gas on both Venus, which has a hellishly thick atmosphere, and Mars. Though the Red Planet once had a much thicker atmosphere long ago, today it is very thin. Scientists are still investigating how this atmospheric loss occurred, but suggest that the sun might have pushed light molecules out of Mars’ upper atmosphere that could not be held in by the planet’s gravity. Life may have existed on Mars in the ancient past, but scientists aren’t sure if that was possible then — or even now.

Might Proxima b be hospitable to life? Scientists are eager to look at the exoplanet in more detail, but Snellen notes that even better telescopes will be needed to answer that question. He suggests that the European Extremely Large Telescope could do the job after construction of the massive observatory is completed in the next decade. It would be able to probe for oxygen, which is a more definitive sign of life.

Meanwhile, the Breakthrough Starshot Initiative, which aims to one day send ultra-fast nanoprobes to the Alpha Centauri star system, is planning to soon begin examining the system’s three stars. The initiative recently partnered with the European Southern Observatory’s Very Large Telescope to look for worlds that could be habitable.


Astronomers Find Stratrosphere On Alien World

August 10, 2017 by  
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A huge, superhot alien planet has a stratrosphere, like Earth does, a new study suggests. 

“This result is exciting because it shows that a common trait of most of the atmospheres in our solar system — a warm stratosphere — also can be found in exoplanet atmospheres,” study co-author Mark Marley, of NASA’s Ames Research Center in California’s Silicon Valley, said in a statement.

“We can now compare processes in exoplanet atmospheres with the same processes that happen under different sets of conditions in our own solar system,” Marley added. [Gallery: The Strangest Alien Planets] 

The research team, led by Thomas Evans of the University of Exeter in England, detected spectral signatures of water molecules in the atmosphere of WASP-121b, a gas giant that lies about 880 light-years from Earth. These signatures indicate that the temperature of the upper layer of the planet’s atmosphere increases with the distance from the planet’s surface. In the bottom layer of the atmosphere, the troposphere, the temperature decreases with altitude, study team members said.

WASP-121b lies incredibly close to its host star, completing one orbit every 1.3 days. The planet is a “hot Jupiter”; temperatures at the top of its atmosphere reach a sizzling 4,500 degrees Fahrenheit (2,500 degrees Celsius), researchers said.

“The question [of] whether stratospheres do or do not form in hot Jupiters has been one of the major outstanding questions in exoplanet research since at least the early 2000s,” Evans told “Currently, our understanding of exoplanet atmospheres is pretty basic and limited. Every new piece of information that we are able to get represents a significant step forward.”

The discovery is also significant because it shows that atmospheres of distant exoplanets can be analyzed in detail, said Kevin Heng of the University of Bern in Switzerland, who is not a member of the study team. 

“This is an important technical milestone on the road to a final goal that we all agree on, and the goal is that, in the future, we can apply the very same techniques to study atmospheres of Earth-like exoplanets,” Heng told “We would like to measure transits of Earth-like planets. We would like to figure out what type of molecules are in the atmospheres, and after we do that, we would like to take the final very big step, which is to see whether these molecular signatures could indicate the presence of life.”

Available technology does not yet allow such work with small, rocky exoplanets, researchers said. 

“We are focusing on these big gas giants that are heated to very high temperatures due to the close proximity of their stars simply because they are the easiest to study with the current technology,” Evans said. “We are just trying to understand as much about their fundamental properties as possible and refine our knowledge, and, hopefully in the decades to come, we can start pushing towards smaller and cooler planets.”

WASP-121b is nearly twice the size of Jupiter. The exoplanet transits, or crosses the face of, its host star from Earth’s perspective. Evans and his team were able to observe those transits using an infrared spectrograph aboard NASA’s Hubble Space Telescope.

“By looking at the difference in the brightness of the system for when the planet was not behind the star and when it was behind the star, we were able to work out the brightness and the spectrum of the planet itself,” Evans said. “We measured the spectrum of the planet using this method at a wavelength range which is very sensitive to the spectral signature of water molecules.”

The team observed signatures of glowing water molecules, which indicated that WASP-121b’s atmospheric temperatures increase with altitude, Evans said. If the temperature decreased with altitude, infrared radiation would at some point pass through a region of cooler water-gas, which would absorb the part of the spectrum responsible for the glowing effect, he explained. 

There have been hints of stratospheres detected on other hot Jupiters, but the new results are the most convincing such evidence to date, Evans said.

“It’s the first time that it has been done clearly for an exoplanet atmosphere, and that’s why it’s the strongest evidence to date for an exoplanet stratosphere,” he said. 

He added that researchers might be able to move closer to studying more Earth-like planets with the arrival of next-generation observatories such as NASA’s James Webb Space Telescope and big ground-based observatories such as the Giant Magellan Telescope (GMT), the European Extremely Large Telescope (E-ELT) and the Thirty Meter Telescope (TMT). JWST is scheduled to launch late next year, and GMT, E-ELT and TMT are expected to come online in the early to mid-2020s.


Did An Asteroid Impact Shape Mars Future

July 27, 2017 by  
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The peculiar geological features on Mars have long puzzled astronomers and planetary scientists. The north of the planet is mostly smooth lowlands while the south is higher and full of craters, and the Red Planet’s interior has a striking abundance of rare metals.

Researchers have proposed various explanations for these elements, positing that they may have been shaped by such forces as ancient oceans, extraterrestrial plate tectonics, or a massive asteroid strike. The latter idea, known as the “single impact hypothesis,” has picked up steam of late, and was just given a shot in the arm by a new paper that argues that the sculpting of Mars and its two small moons was largely determined by a huge impact early in the solar system’s history.

In this scenario, a celestial body that was roughly the size of Ceres, a dwarf planet in the asteroid belt, collided with the Red Planet and tore away a part of its northern hemisphere, leaving behind large deposits of metallic elements. Additionally, debris from the asteroid circled the planet and eventually coalesced into Phobos and Deimos, the two tiny moons that orbit Mars — at least for now. (Scientists estimate that Phobos will either break up or slam into Mars in a few million years.)

Hosted by Hanneke Weitering On July 21, 1961, NASA astronaut Gus Grissom completed the second successful human spaceflight mission for the United States of America. His suborbital flight in the Liberty Bell 7 capsule lasted 15 minutes and 30 seconds and reached an altitude of 103 nautical miles. Everything went according to plan until just after Grissom splashed down in the Atlantic Ocean. While Grissom was waiting on the recovery crew to come get him, the hatch cover on Liberty Bell 7 unexpectedly blew open and water started pouring into the capsule. Grissom barely made it out alive, but Liberty Bell 7 sank into the ocean.

“We showed in this paper — that from dynamics and from geochemistry — that we could explain these three unique features of Mars,” said Stephen Mojzsis, a professor in the University of Colorado Boulder’s department of geological sciences and a co-author of the paper, in a statement. “This solution is elegant, in the sense that it solves three interesting and outstanding problems about how Mars came to be.”

The research, which Mojzsis produced in collaboration with Ramon Brasser, an astronomer at the Earth-Life Science Institute at the Tokyo Institute of Technology in Japan, was recently published in Geophysical Research Letters. It looked at Martian meteorite samples that landed on Earth. These samples had more rare metals (like iridium, osmium or platinum) than expected, hinting that Mars received a lot of impacts from small, rocky asteroids that carried these elements with them.

The scientists estimated that these rare metals account for about 0.8% of the mass of Mars.

They then ran simulations with asteroids of various sizes to determine what size would best fit the Martian geology. The answer was a huge asteroid about 745 miles across (1,200 kilometers) — nearly the length of the state of California. The simulations suggest this behemoth slammed into Mars about 4.43 billion years ago, just 700 million years after the solar system was formed. Several smaller impacts occurred in the eons that followed.

The researchers theorize that after the big impact took place, there were distinct areas of asteroid material and Red Planet rock on the surface. Over time, however, erosion, wind, and other processes on the surface swept the two reservoirs together in a mixture.

Mojzsis and Brasser next plan to use UC Boulder’s Martian meteorite archives to see how the composition of these meteorites differs or remains the same, depending on how old the meteorites are.


Is Titan A Better Location Than Mars For Colonization

July 26, 2017 by  
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NASA and Elon Musk’s SpaceX are focused on getting astronauts to Mars and even one day establishing a colony on the Red Planet — but what if their attention is better directed elsewhere? A new paper in the Journal of Astrobiology & Outreach suggests that humans should instead establish a colony on Titan, a soupy orange moon of Saturn that has been likened to an early Earth, and which may harbor signs of “life not as we know it.”

“In many respects, Saturn’s largest moon, Titan, is one of the most Earth-like worlds we have found to date,” NASA says on its website. “With its thick atmosphere and organic-rich chemistry, Titan resembles a frozen version of Earth, several billion years ago, before life began pumping oxygen into our atmosphere.”

To be clear, Titan could have microbes — or, at the least, chemistry that resembles prebiotic life — but it is no Earth. The moon is perpetually covered in an orange cloud, and its atmosphere is not human-friendly. But Titan’s gravity is walkable (14 percent that of Earth), radiation on the surface is less than on Mars due to its thick clouds, and it offers various sources from which visitors might generate energy.

Hosted by Hanneke Weitering On July 20, 1969, human beings walked on the moon for the very first time! Apollo 11 astronauts Neil Armstrong and Buzz Aldrin exited their lunar lander and planted their moon boots on the lunar surface at about 11 p.m. Eastern Time. Armstrong led the way down the ladder. When he took his first step, he famously said, “That’s one small step for a man…one giant leap for mankind.” Once they found their footing, they got straight to work. They inspected the spacecraft to look for any damage from the landing, set up cameras, collected moon rocks and planted the American flag into the soil. They also strolled around the moon to assess the mobility of their spacesuits.

As the paper’s author, Amanda Hendrix, pointed out in a previous book that she co-authored, Beyond Earth: Our Path to a New Home in the Planets, Titan has massive deposits of hydrocarbons — compounds generally associated with petroleum and gas. Data from NASA’s Cassini probe has shown that Titan has hundreds of times more liquid hydrocarbons than all of the known oil and natural gas reserves on Earth.

Beyond Earth points out that people on Titan could get energy from these compounds if they use a separate combustion source that helps circumvent that fact that there’s no oxygen in the moon’s atmosphere. But Hendrix’s new research also discusses other ways of generating chemical energy, such as treating acetylene (an abundant compound) with hydrogen.

“In this paper, I wanted to dig into the chemical energy options a bit deeper and also look into alternative energy possibilities,” said Hendrix, a staff scientist at the non-profit Planetary Science Institute. “My co-author, Yuk Yung, and I looked at chemical, nuclear, geothermal, solar, hydropower, and wind power options at Titan. The paper is designed to be a high-level first look at some of these topics.”

While Hendrix said it’s possible to generate such energy using technology that we have available today, she noted that there are ways that we could get even more out of Titan’s environment with the proper study. For example, more solar power would be generated if we learned about the capabilities of different photovoltaic cell materials — and most importantly, how they would behave on Titan.

Hydro power would require better mapping of Titan’s abundant lake regions, including their topography and their flow rate. Even wind power would require some research into airborne wind turbines — but Hendrix said all of these options are promising.

“I imagine that, as here on Earth, a combination of energy sources will be useful on Titan,” she said. “In particular, solar energy (using large arrays) and wind power (using airborne wind turbines) may be particularly effective.”

Delivered properly, the energy needs would be more than enough for a small outpost. Instead of just sending humans on a one-shot mission to look for life on the surface, for example, Hendrix envisions a future that could generate power for years. One scenario — solar arrays over 10 percent of Titan’s surface area — would generate power needs of a population of roughly 300 million, equivalent to that of the United States.

“This is just an initial estimate, of course, but what we’re talking about is something much larger than a short-term human science mission to Titan,” Hendrix said.

With NASA’s stated goal of sending humans to Mars by the 2030s, however, space agencies remain focused on Mars exploration. While the Cassini robotic mission at Saturn and its moons wraps up observations this September, NASA and the European Space Agency are planning even more missions to Mars in the coming years. Saturn doesn’t really figure into the plans, although NASA is thinking about eventual missions to Uranus, Neptune, and Jupiter’s moon Europa.


Does Uranus Have An Odd Magnetic Field

July 18, 2017 by  
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The planet Uranus just keeps getting weirder.

The icy gas world that strangely orbits the sun on its side may also have a wonky magnetic field that constantly flickers on and off, new research suggests.

Magnetic fields around planets, or magnetospheres, create shields against the bombardment of radiation from the sun known as solar wind. On Earth, for example, the magnetosphere lines up pretty closely with the planet’s axis of rotation, and magnetic field lines emerge from Earth’s north and south poles. On Uranus, however, the magnetosphere is a bit more chaotic.

Uranus’ spin axis is tilted by a whopping 98 degrees, and the planet’s off-center magnetic field is tilted by another 60 degrees. Every time the planet rotates (about every 17.24 hours), this lopsided magnetic field tumbles around, opening and closing periodically as the magnetic field lines disconnect and reconnect, the study found. 

Researchers at the Georgia Institute of Technology (Georgia Tech) in Atlanta figured this out by simulating Uranus’ messy magnetosphere using numerical models and data from NASA’s Voyager 2 spacecraft, which flew by the planet in 1986.

“Uranus is a geometric nightmare,” Carol Paty, an associate professor at Georgia Tech’s School of Earth & Atmospheric Sciences and co-author of the study, said in a statement. “The magnetic field tumbles very fast, like a child cartwheeling down a hill head over heels. When the magnetized solar wind meets this tumbling field in the right way, it can reconnect, and [so] Uranus’ magnetosphere goes from open to closed to open on a daily basis.”

When the magnetosphere opens up, it allows solar particles to bombard the planet. Then, when the magnetic field lines reconnect, this natural shield can continue to block the solar wind.

This process may be related to auroras on Uranus. Just like the auroras on Earth and other planets, Uranus’ atmosphere lights up when particles from the solar wind enter it and interact with gases like nitrogen and oxygen. 

NASA’s Hubble Space Telescope has previously observed auroras on Uranus, but astronomers face difficulties in studying how these auroras interact with the magnetosphere, because the planet is so far away — nearly 2 billion miles (3.2 billion kilometers) from Earth. The space agency is currently considering sending another spacecraft to Uranus and Neptune to investigate those planet’s magnetic fields, among other things.

Xin Cao, a Ph.D. candidate at Georgia Tech who led the study, said that studying Uranus can teach scientists a lot about planets outside of the solar system. “The majority of exoplanets [worlds outside the solar system] that have been discovered appear to also be ice giants in size,” he said. “Perhaps what we see on Uranus and Neptune is the norm for planets: very unique magnetospheres and less-aligned magnetic fields.

“Understanding how these complex magnetospheres shield exoplanets from stellar radiation is of key importance for studying the habitability of these newly discovered worlds,” Cao added.

The results of this study were published June 27 in the Journal of Geophysical Research: Space Physics.


Is Mars Soil Toxic To Microbes

July 17, 2017 by  
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The Martian surface may be even less hospitable to life than scientists had thought.

Ultraviolet (UV) radiation streaming from the sun “activates” chlorine compounds in the Red Planet’s soil, turning them into potent microbe-killers, a new study suggests.

These compounds, known as perchlorates, seem to be widespread in the Martian dirt; several NASA missions have detected them at a variety of locations. Perchlorates have some characteristics that would appear to boost the Red Planet’s habitability. They drastically lower the freezing point of water, for example, and they offer a potential energy source for microorganisms, scientists have said.

But the new study, by Jennifer Wadsworth and Charles Cockell — both of the U.K. Centre for Astrobiology at the University of Edinburgh in Scotland —  paints perchlorates in a different light. The researchers exposed the bacterium Bacillus subtilis, a common spacecraft contaminant, to perchlorates and UV radiation at levels similar to those found at and near the Martian surface. (Because Mars’ atmosphere is just 1 percent as thick as that of Earth, UV fluxes are much higher on the Red Planet than on Earth.)

The bacterial cells lost viability within minutes in Mars-like conditions, the researchers found. And the results were even more dramatic when Wadsworth and Cockell added iron oxides and hydrogen peroxide, two other common components of Martian regolith, to the mix: Over the course of 60 seconds, the combination of irradiated perchlorates, iron oxides and hydrogen peroxide boosted the B. subtilis death rate by a factor of 10.8 compared to cells exposed to UV radiation alone, the researchers found.

“These data show that the combined effects of at least three components of the Martian surface, activated by surface photochemistry, render the present-day surface more uninhabitable than previously thought and demonstrate the low probability of survival of biological contaminants released from robotic and human exploration missions,” Wadsworth and Cockell wrote in the study, which was published online today (July 6) in the journal Scientific Reports. (Scientists already knew about perchlorates’ toxic potential, but it usually takes high temperatures to “activate” the compounds, Wadsworth told

It’s unclear how deep this inferred “uninhabitable zone” goes on Mars, because the precise mechanism behind the cell-killing action isn’t understood, Wadsworth said.

“If you’re looking for life, you have to additionally keep the ionizing radiation in mind that can penetrate the top layers of soil, so I’d suggest digging at least a few meters into the ground to ensure the levels of radiation would be relatively low,” she told via email.

The European/Russian ExoMars rover, which is scheduled to launch toward the Red Planet in 2020 on a mission to search for signs for life, will feature a drill that can reach a maximum depth of 6.5 feet (2 m).

There’s an important caveat to the new results, however: B. subtilis is a garden-variety microbe, not an “extremophile” adapted to survive in harsh conditions, the researchers said.

“It’s not out of the question that hardier life forms would find a way to survive” at or near the Martian surface, Wadsworth told “It’s important we still take all the precautions we can to not contaminate Mars.”


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