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Astronomers Ponder The Role Of Physics In Life

September 25, 2017 by  
Filed under Around The Net

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.

Courtesy-Space

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. 

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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.

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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.

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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.

 

Courtesy-Space

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 Space.com 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.”

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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.

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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 Space.com. “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 Space.com. “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.

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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.

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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.

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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 Space.com.)

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 Space.com 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 Space.com. “It’s important we still take all the precautions we can to not contaminate Mars.”

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NASA Finds More Alien Worlds

June 28, 2017 by  
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NASA announced the latest crop of planet discoveries from the Kepler Space Telescope during a briefing on Monday morning June 19. 

The briefing will be at 11 a.m. EDT (1500 GMT) during the Kepler Science Conference at NASA’s Ames Research Center in California. You can watch the exoplanet announcement here, courtesy of NASA TV. NASA will livestream the conference.

The briefing will incude a panel of four experts, according to a statement by NASA: Mario Perez, Kepler program scientist in the Astrophysics Division of NASA’s Science Mission Directorate in Washington; Susan Thompson, Kepler research scientist at the SETI Institute in Mountain View, California; Benjamin Fulton, doctoral candidate at the University of Hawaii at Manoa and the California Institute of Technology; and Courtney Dressing, NASA Sagan Fellow at the California Institute of Technology. A question-and-answer session will follow.

Kepler has been hunting for extrasolar planets since its launch in 2009. This latest set of exoplanet candidates will use a more complete data set than ever before, with analysis of greater sophistication. The spacecraft started a new mission, called K2, after the failure of two reaction wheels that stabilized the spacecraft in 2013. The K2 mission was a modified version of the original planet-hunting mandate, seeking worlds around relatively nearby red dwarf stars. 

Newfound exoplanets are often listed as candidates because it can take time to verify that they are actually there. Kepler finds planets by observing the light of stars over a period of time, using a process called the transit method. If the light dims, then it’s possible a planet passed in front of it. The evidence for an exoplanet is considered stronger if the light dims more than once on a predictable schedule, indicating that something is in orbit around the star. 

Kepler was the first mission capable of seeing planets the size of Earth around other stars in the “habitable zone” — the region at a distance from a star where liquid water could exist without freezing or boiling away immediately. 

According to NASA, thus far Kepler has found 4,496 exoplanet candidates. Some 2,335 have been confirmed and 21 are Earth-size planets in the habitable zone. Since the mission was renamed K2, an additional 520 exoplanet candidates have been found, with 148 confirmed.

 

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Do The Halos On Mars Suggest Life Condition Lasted Longer

June 15, 2017 by  
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Mars was capable of supporting life for much longer in the ancient past than researchers had thought, a new study suggests.

Shortly after touching down inside the Red Planet’s 96-mile-wide (154 kilometers) Gale Crater in August 2012, NASA’s Curiosity rover found evidence that the area had harbored a potentially habitable lake-and-stream system in the ancient past. 

Now, Curiosity has spotted “halos” of silica-rich bedrock surrounding fractures near Gale’s floor. These halos were found overlying ancient lake sediments with a high silica content, mission scientists said.

“This tells us that the silica found in halos in younger rocks close by was likely remobilized from the old sedimentary rocks by water flowing through the fractures,” study lead author Jens Frydenvang, a scientist at Los Alamos National Laboratory in New Mexico and the University of Copenhagen in Denmark, said in a statement.

“What this finding tells us is that, even when the lake eventually evaporated, substantial amounts of groundwater were present for much longer than we previously thought, thus further expanding the window for when life might have existed on Mars,” Frydenvang added.

The new study bolsters other Curiosity results announced in December, which suggest that, long ago, Gale may have been able to support microbial life for hundreds of millions of years consecutively.

The silica halos — which Curiosity studied with its cameras, X-ray spectrometer and laser-firing Chemistry and Camera instrument — lie on the lower north slope of Mount Sharp, a 3.4-mile-high (5.5 km) mountain that rises out of Gale Crater’s center.

Curiosity has been climbing through Mount Sharp’s foothills since September 2014, analyzing the rock layers along the way for information about Mars’ evolution from a relatively warm and wet world long ago to the cold and dry planet it is today.

That shift is associated with the loss of Mars’ thick, carbon-dioxide-dominated atmosphere. Fast-moving solar particles had stripped away the vast majority of the Red Planet’s air by 3.7 billion years ago or so, according to observations by NASA’s Mars Atmosphere and Volatile Evolution orbiter (MAVEN).

This solar stripping began in earnest shortly after Mars lost its global magnetic field, which had served as a shield against these solar particles, MAVEN scientists have said. 

Curiosity has now traveled more than 10 miles (16 km) on the Martian surface. The record for the longest distance covered on an alien world belongs to Curiosity’s older, smaller cousin, Opportunity, which has racked up 27.86 miles (44.8 km) since its January 2004 touchdown.

The new study was published online today (May 30) in the journal Geophysical Research Letters.

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NASA To Focus New Horizon On Another Object Beyond Pluto

June 14, 2017 by  
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The team behind NASA’s New Horizons mission is about to get some good looks at the Pluto probe’s next flyby target, if everything goes according to plan.  

New Horizons is speeding toward a Jan. 1, 2019, close encounter with a small object called 2014 MU69, which lies about 1 billion miles (1.6 billion kilometers) beyond the orbit of Pluto.

On Saturday (June 3), 2014 MU69 will cross in front of a distant star in an “occultation” visible from a narrow band of land and sea in the Southern Hemisphere. Stellar occultations can reveal key details about the light-blocking foreground body, so New Horizons team members have deployed to Argentina and South Africa to watch the show.

“Our primary objective is to determine if there are hazards near MU69 — rings, dust or even satellites — that could affect our flight planning,” New Horizons principal investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado, said in a statement.

“But we also expect to learn more about its orbit, and possibly determine its size and shape,” Stern added. “All of that will help feed our flyby planning effort.”

Astronomers have not been able to nail down 2014 MU69’s precise orbit yet; as its name suggests, the object was discovered just three years ago. So the New Horizons team used images of MU69 taken by NASA’s Hubble Space Telescope and star-mapping data from Europe’s Gaia mission to determine where MU69’s shadow will fall on Earth on Saturday.

The researchers have access to more than two dozen fixed-base telescopes along this projected shadow path. And they brought along 25 portable telescopes, 22 of which are new, 16-inch (40 centimeters) instruments, mission team members said.

The team will space out the telescopes, placing one every 6 to 18 miles (10 to 29 km) along the path. This strategy will increase the chances that at least one instrument will get a good enough look at the 2-second-long occultation to help researchers determine MU69’s size, reflectivity and other key characteristics, team members said. (2014 MU69 is thought to be about 25 miles, or 40 km, across.)

“Deploying on two different continents also maximizes our chances of having good weather,” New Horizons deputy project scientist Cathy Olkin, also from SwRI, said in the same statement. “The shadow is predicted to go across both locations, and we want observers at both, because we wouldn’t want a huge storm system to come through and cloud us out — the event is too important and too fleeting to miss.”

The team will have two chances to gather similar data next month as well: 2014 MU69 will occult another star on July 10, and a different one on July 17. New Horizons scientists will observe both events. And they plan to use NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) — a 747 jet outfitted with a 100-inch (254 cm) telescope — during the July 10 occultation, mission team members said.

SOFIA will allow the team to get above any inclement weather as well as maneuver into the middle of the shadow path.

New Horizons famously flew by Pluto in July 2015, giving humanity its first-ever up-close looks at that diverse and complex world. The mission team was able to start mapping out the Pluto encounter nearly seven years ahead of time, researchers said. The timeline is more compressed with 2014 MU69, because New Horizons’ handlers couldn’t begin focusing on this second target until Pluto was in the probe’s rearview mirror.

“Spacecraft flybys are unforgiving,” Stern said. “There are no second chances. The upcoming occultations are valuable opportunities to learn something about MU69 before our encounter, and help us plan for a very unique flyby of a scientifically important relic of the solar system’s era of formation.”

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Can Tiny Interstellar Probes Test The Panspermia Theory

June 9, 2017 by  
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Some of the first spacecraft that humanity sends to other solar systems may carry microscopic ambassadors from Earth.

The $100 million Breakthrough Starshot initiative is working to develop the technology required to accelerate tiny, sail-equipped probes to 20 percent the speed of light, using powerful lasers. 

If everything goes well, large fleets of these 1-gram spacecraft could begin launching toward Proxima b and other nearby alien worlds within 20 years or so, project representatives have said. The probes would characterize these planets in detail and search for signs of life, but some could perform other work as well.

For example, Breakthrough Starshot adviser Jeff Kuhn, a physicist at the University of Hawaii, said that the project offers a great opportunity to investigate the feasibility of interstellar panspermia — the idea that life might have spread from place to place throughout the Milky Way galaxy, and perhaps even the larger universe.

During a panel discussion on April 21 at the Breakthrough Discuss conference in Stanford, California, Kuhn noted that spores of the bacteria species Bacillus subtilis can survive for at least six years when exposed to the space environment. 

“I think it would be fun, on one of these disposable chips, to put a little colony of Bacillus, send it for 20 years, turn it on, give it some nutrients and see if it’s still alive, just to experimentally decide whether or not panspermia works over interstellar distances,” Kuhn said.

That comment elicited a response from audience member Philip Lubin, a physics professor at the University of California, Santa Barbara, who’s a key player in the development of Breakthrough Starshot’s laser-propulsion system.

“A part of our program — at least on the NASA side, because we haven’t cleared this with Breakthrough yet — is actually to put organisms to sleep, in stasis mode,” Lubin said at the conference. (Lubin and his group are also developing projects with the aid of NASA grant money.)

“And there are certain organisms known as C. elegans, which we’re going to embed human DNA into and send them out and then awaken them on arrival,” Lubin added, referring to a tiny roundworm species that’s a common study animal for biologists. “However, I expect that will be a highly controversial thing to do.”

The panspermia hypothesis posits that Earth life might have arrived, rather than originated, here.

This idea is not as fringe as you may think. For example, some scientists argue that, in the ancient past, the Martian environment was more conducive to life’s emergence than that of Earth. 

And it’s not terribly uncommon for the two planets to exchange material, in the form of rocks and dirt blasted into space by asteroid strikes. Orbital dynamics dictates that it’s much easier for Martian stuff to reach Earth than the other way around, so we may all be Martians, according to this line of thinking.

It may even be possible for life-forms to move from one star system to another, some panspermia adherents say. For example, hardy microscopic spores could be transported vast distances by stellar radiation pressure. Or frigid bodies orbiting far from their parent stars could come under the gravitational sway of a neighboring sun. [5 Bold Claims of Alien Life]

“We know that there are interstellar carriers: The Oort Cloud easily transfers from one solar system to another,” Kuhn said. (The Oort Cloud is our own solar system’s huge comet repository, which is believed to begin about 0.8 light-years from the sun.)

But there are a number of factors that could make it difficult for life to move through space. 

For example, putative Martian microbes ejected by an asteroid or comet strike would have to survive the intense heat and pressure of the impact, the harsh temperatures and high radiation levels of deep space and the rigors of atmospheric entry to have any hope of colonizing Earth. (The B. subtilis in the long-term experiment cited by Kuhn were in low Earth orbit, which has a more benign radiation environment thanks to our planet’s magnetic field.) 

Then, there’s the issue of time, which makes interstellar panspermia unlikely, according to Harvard University astronomy professor Dimitar Sasselov.

“With the short-lived universe we live in, the more likely scenario is that most of the planets that we’ll see life on are also the locations where it emerged from the planetary conditions,” Sasselov, who’s also the founding director of the Harvard Origins of Life Initiative, said during a different panel discussion at Breakthrough Discuss on April 20.

The transfer of organisms between nearby planets in the same solar system is feasible, he added. But interstellar panspermia “just takes too long, and it’s too far of a journey, and the probabilities currently, in the current universe, are just too small,” Sasselov said.

All of the above speculation assumes naturally occurring “accidental” panspermia. But it’s also possible that intelligent aliens could set panspermia in motion, either unintentionally (via contaminated spacecraft) or intentionally (in an effort to seed other worlds), some scientists have said.

Breakthrough Starshot, and projects like it, could give humanity this ability as well.

“We can be the panspermia which actually seeds other planets if we want,” Lubin said. “And it’s something to think about for the future.”

Now that would be controversial.

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