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Does Pluto Have Buried Oceans

December 7, 2017 by  
Filed under Around The Net

Our solar system may harbor many more potentially habitable worlds than scientists had thought.

Subsurface oceans could still slosh beneath the icy crusts of frigid, faraway worlds such as the dwarf planets Pluto and Eris, kept liquid by the heat-generating tug of orbiting moons, according to a new study. 

“These objects need to be considered as potential reservoirs of water and life,” lead author Prabal Saxena, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. “If our study is correct, we now may have more places in our solar system that possess some of the critical elements for extraterrestrial life.”  

Underground oceans are known, or strongly suspected, to exist on a number of icy worlds, including the Saturn satellites Titan and Enceladus and the Jovian moons Europa, Callisto and Ganymede. These oceans are kept liquid to this day by “tidal heating”: The powerful gravitational pull of these worlds’ giant parent planets stretches and flexes their interiors, generating heat via friction.

The new study suggests something similar may be going on with Pluto, Eris and other trans-Neptunian objects (TNOs).

Many of the moons around TNOs are thought to have coalesced from material blasted into space when objects slammed into their parent bodies long ago. That’s the perceived origin story for the one known satellite of Eris (called Dysnomia) and for Pluto’s five moons (as well as for Earth’s moon). 

Such impact-generated moons generally begin their lives in relatively chaotic orbits, team members of the new study said. But over time, these moons migrate to more-stable orbits, and as this happens, the satellites and the TNOs tug on each other gravitationally, producing tidal heat.

Saxena and his colleagues modeled the extent to which this heating could warm up the interiors of TNOs — and the researchers got some intriguing results.

“We found that tidal heating can be a tipping point that may have preserved oceans of liquid water beneath the surface of large TNOs like Pluto and Eris to the present day,” study co-author Wade Henning, of NASA Goddard and the University of Maryland, said in the same statement.

As the term “tipping point” implies, there’s another factor in play here as well. It’s been widely recognized that TNOs could harbor buried oceans thanks to the heat produced by the decay of the objects’ radioactive elements. But just how long such oceans could persist has been unclear. This type of heating peters out eventually, as more and more radioactive material decays into stable elements. And the smaller the object, the faster it cools down.

Tidal heating may do more than just lengthen subsurface oceans’ lives, researchers said.Next Up

“Crucially, our study also suggests that tidal heating could make deeply buried oceans more accessible to future observations by moving them closer to the surface,” said study co-author Joe Renaud, of George Mason University in Virginia. “If you have a liquid-water layer, the additional heat from tidal heating would cause the next adjacent layer of ice to melt.” 

The new study was published online last week in the journal Icarus

Courtesy-Space

Does Space Dust Transport Life Around The Galaxy

November 29, 2017 by  
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It may not take an asteroid strike to transport life from one planet to another.

Fast-moving dust could theoretically knock microbes floating high up in a world’s atmosphere out into space, potentially sending the bugs on a trip to another planet — perhaps even one orbiting a different star, according to a new study.

“The proposition that space-dust collisions could propel organisms over enormous distances between planets raises some exciting prospects of how life and the atmospheres of planets originated,” study author Arjun Berera, a professor in the School of Physics and Astronomy at the University of Edinburgh in Scotland, said in a statement.  

“The streaming of fast space dust is found throughout planetary systems and could be a common factor in proliferating life,” Berera added.

Berera isn’t the first person to propose that organisms could hop from world to world throughout the cosmos. That basic idea, known as panspermia, has been around for thousands of years. It has received renewed interest recently, however, as scientists have demonstrated that some organisms — such as certain bacteria, and micro-animals known as tardigrades — can survive for extended periods in space.

But researchers have generally regarded comet or asteroid impacts as the only viable way to get simple life-forms off a planet and into space, whence they could perhaps blunder their way to a different habitable world. (We won’t consider here the “directed panspermia” idea, which posits that intelligent aliens have seeded the galaxy with life or its building blocks.)

Comet or asteroid impacts do indeed blast rocks from planet to planet. Scientists have found numerous meteorites here on Earth that were once part of Mars — including one known as ALH84001, which some scientists think may preserve signs of ancient Red Planet life.

In the new study, Berera examined what likely happens when bits of interplanetary dust hit molecules and particles in Earth’s atmosphere. This space stuff rains down on us every day, hitting the planet at speeds of between 22,400 mph and 157,000 mph (36,000 to 253,000 km/h).

He calculated that small particles floating at least 93 miles (150 kilometers) above Earth’s surface could theoretically get knocked into space by this wandering dust. It’s unclear if microbes could survive such violent collisions; that’s an area ripe for future research, Berera wrote in the new paper, which has been accepted for publication in the journal Astrobiology. (You can read the study for free at the online preprint site arXiv.org.)

And even if these micro-impacts are invariably fatal, they could still help life get a foothold on other worlds by sending its building blocks — the complex molecules that make up a microbe corpse, for example — out into space, he added.

Courtesy-Space

Astronomers Find New Alien Planet Suitable For Life

November 21, 2017 by  
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A newfound exoplanet may be one of the best bets to host alien life ever discovered — and it’s right in Earth’s backyard, cosmically speaking.

Astronomers have spotted a roughly Earth-mass world circling the small, dim star Ross 128, which lies just 11 light-years from the sun. The planet, known as Ross 128b, may have surface temperatures amenable to life as we know it, the researchers announced in a new study that will appear in the journal Astronomy & Astrophysics.

Ross 128b is 2.6 times more distant from Earth than Proxima b, the potentially habitable planet found in the nearest solar system to the sun. But Proxima b’s parent star, Proxima Centauri, blasts out a lot of powerful flares, potentially bathing that planet in enough radiation to stunt the emergence and evolution of life, scientists have said. [10 Exoplanets That Could Host Alien Life]

Radiation is likely much less of an issue for Ross 128b, because its parent star is not an active flarer, said discovery team leader Xavier Bonfils, of the Institute of Planetology and Astrophysics of Grenoble and the University of Grenoble Alpes in France.

“This is the closest Earth-mass planet potentially in the habitable zone that orbits a quiet star,” Bonfils told Space.com

Bonfils and his colleagues found Ross 128b using the High Accuracy Radial velocity Planet Searcher (HARPS), an instrument at the European Southern Observatory’s La Silla Observatory in Chile.

As its name suggests, HARPS employs the “radial velocity” method, noticing the wobbles in a star’s movement induced by the gravitational tugs of orbiting planets. (NASA’s prolific Kepler space telescope, by contrast, uses the “transit” technique, spotting tiny brightness dips caused when a planet crosses its host star’s face from the spacecraft’s perspective.)

The HARPS observations allowed Bonfils and his team to determine that Ross 128b has a minimum mass 1.35 times that of Earth, and that the planet orbits its host star once every 9.9 Earth days.

Such a tight orbit would render Ross 128b uninhabitable in our own solar system. But Ross 128 is much cooler than the sun, so the newfound world is likely temperate, the researchers said. Determining whether  the planet is actually capable of supporting life as we know it, however, would require a better understanding of its atmosphere, Bonfils said.

“Ross 128b receives 1.38 times [more] irradiation than Earth from our sun,” he said. “Some models made by theorists say that a wet Earth-size planet with such irradiation would form high-altitude clouds. Those clouds would reflect back to space a large fraction of the incident light, hence preventing too much greenhouse heating. With those clouds, the surface would remain cool enough to allow liquid water at the surface. Not all models agree, though, and others predict this new planet is rather like Venus.

Though both Ross 128 and Proxima Centauri are red dwarfs — the most common type of star in the Milky Way galaxy — they are very different objects.

“Proxima Centauri is particularly active, with frequent, powerful flares that may sterilize (if not strip out) its atmosphere,” Bonfils said. “Ross 128 is one of the quietest stars of our sample and, although it is a little further away from us (2.6x), it makes for an excellent alternative target.”

And the star may indeed be targeted in the not-too-distant-future — by giant ground-based instruments such as the European Extremely Large Telescope, the Giant Magellan Telescope and the Thirty Meter Telescope, all of which are scheduled to be up and running by the mid-2020s.

Such megascopes should be able to resolve Ross 128b and even search its atmosphere for oxygen, methane and other possible signs of life, Bonfils said. (NASA’s $8.9 billion James Webb Space Telescope, which is scheduled to launch in early 2019, probably won’t be able to perform such a biosignature search, the researchers said in their discovery paper. If Ross 128b transited its host star from Webb’s perspective, it would likely be a different story, they added.)

Earlier this year, by the way, radio astronomers detected a strange signal that seemed to be emanating from Ross 128. But further investigation revealed that the signal most likely came from an Earth-orbiting satellite, not an alien civilization.

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Is Another Mission To Pluto Being Planned

October 31, 2017 by  
Filed under Around The Net

A grassroots movement seeks to build momentum for a second NASA mission to the outer solar system, a generation after a similar effort helped give rise to the first one.

That first mission, of course, was New Horizons, which in July 2015 performed the first-ever flyby of Pluto and is currently cruising toward a January 2019 close encounter with a small object known as 2014 MU69.

New Horizons got its start with letter-writing campaigns in the late 1980s, and the new project hopes to duplicate that success, said campaign co-leader Kelsi Singer, a New Horizons team member who’s based at the Southwest Research Institute (SwRI) in Boulder, Colorado.   

Nearly three dozen scientists have drafted letters in support of a potential return mission to Pluto or to another destination in the Kuiper Belt, the ring of icy bodies beyond Neptune’s orbit, Singer told Space.com.Next Up

These letters have been sent to NASA planetary science chief Jim Green, as well as to the chairs of several committees that advise the agency, she added.

“We need the community to realize that people are interested,” Singer said. “We need the community to realize that there are important, unmet goals. And we need the community to realize that this should have a spot somewhere in the Decadal Survey.”

That would be the Planetary Science Decadal Survey, a report published by the National Academy of Sciences that lays out the nation’s top exploration priorities for the coming decade.

“This is the way it normally works,” said New Horizons principal investigator Alan Stern, who’s also based at SwRI.

“First it bubbles up in the community and then, when there’s enough action, the agency starts to get behind it,” Stern, who has been the driving force behind New Horizons since the very beginning, told Space.com. “Then it lets the Decadal Survey sort things out.”

Stern contributed a letter to the new campaign, and he has voiced support for a dedicated Pluto orbiter. Singer would also be happy if NASA went back to the dwarf planet.

“Pluto just has so much going on,” she said.

But there are other exciting options available as well, Singer said. For example, NASA could do a flyby of a different faraway dwarf planet — Eris, perhaps — to get a better idea of the variety and diversity of these intriguing worlds.

Or the agency could target Kuiper Belt objects (KBOs) that have diameters of a few hundred kilometers or so, she added. New Horizons has flown by one “big” KBO (Pluto) and will soon see a small one — 2014 MU69 is just 20 miles (32 km) or so across — but there are no plans at the moment to study anything of an intermediate size up close.

The last Decadal Survey was put out in 2011, and it covers the years 2013 to 2022. The next one is due out in five years, and it will help map out NASA’s plans for the 2020s and early 2030s. So Singer knows she and her colleagues must be patient, even if their letter-writing campaign ultimately bears fruit.

“I would say 25 years is the longest I think about,” she said, referring to how long it may be before another Kuiper Belt mission gets to its destination. “And I hope it may be more like 15 years.”

Courtesy-Space

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.

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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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.

 

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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.

Courtesy-Space

Astronomers Find Stratrosphere On Alien World

August 10, 2017 by  
Filed under Around The Net

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.

Courtesy-Space

Does Uranus Have An Odd Magnetic Field

July 18, 2017 by  
Filed under Around The Net

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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NASA Finds More Alien Worlds

June 28, 2017 by  
Filed under Around The Net

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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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.

Courtesy-Space

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