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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. 

Courtesy-Space

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.

Courtesy-Space

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.”

Courtesy-Space

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  
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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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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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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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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.”

Courtesy-Space

Can Tiny Interstellar Probes Test The Panspermia Theory

June 9, 2017 by  
Filed under Around The Net

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

Does Trappist-1 Planets Have Moons

June 5, 2017 by  
Filed under Around The Net

While we know of thousands of exoplanets and exoplanet candidates, the search for moons outside of our solar system is just beginning. We don’t have a confirmed exomoon discovery yet, but they’re bound to be out there.

Finding exomoons will help us better understand habitability on Earth. Some experts say a reason that life arose is our own moon is so close to the size of our planet, which stabilized its axis rotation. However, other studies (such as this 2011 American Astronomical Society paper quoted in a NASA Astrobiology story) argue that the gravitational influence of other planets in our solar system provide enough stability.

A new study looks at the possibilities of large moons in TRAPPIST-1, a notoriously crowded exoplanet system that may have habitable planets within it. Earlier this year, observations from NASA’s Spitzer Space Telescope indicated that seven planets here could be rocky and have liquid water on their surfaces, making TRAPPIST-1 the system with the most potentially habitable planets.

But even before NASA’s discovery, TRAPPIST-1 was known and pondered by scientists, including the author of the new paper, Stephen Kane, an associate professor of astronomy at San Francisco State University who specializes in exoplanets.

“I have several publications now on exomoons, and for many years I’ve been thinking about how the ability of a planet to host a moon scales with the presence of nearby planets and proximity to the host star,” Kane said in an e-mail. “The discovery of the TRAPPIST-1 system prompted me to finally calculate whether or not planets in compact planetary systems can actually harbor moons.”

Kane cautioned that scientists can’t overly attribute Earth’s habitability to our moon, because Earth is the only known habitable planet. However, the moon does have an important role: It creates significant tides on Earth, which probably helped create the tidal pools in which early biochemistry could occur.

“The presence of the moon has helped to stabilize changes in the tilt of the Earth’s rotational axis, which in turn creates longer periods of climate stability,” Kane added. “So although it’s difficult to say what the Earth would be like without a moon, we can certainly describe ways in which it has positively influenced our present environment.”

For TRAPPIST-1, Kane found that the planets are so tightly packed together that large moons would likely be impossible. While the rotational axes of the planets would quickly change and have more chaotic climates, he said, life could still evolve — it just might take a longer time.

Kane’s methodology involved studying the influences of two parameters: the Hill radius, or the area in space in which a planet exerts gravitational influence based on its mass and distance from the host star, and the Roche limit, which identifies where the gravitational effect near a planet is too strong for a moon to survive.

“A moon can only exist around a planet if it lies between these two boundaries: too close and it will be destroyed, too far away and it will escape the gravitational influence of the planet,” Kane said. “The results of the study described in my paper show that, for most planets in compact planetary systems, the Hill radius and Roche limit are close enough to each other that there is no space in which a moon can exist and so such planets cannot have moons in orbit around them.”

Courtesy-Fud

Do Any Trappist 1 Planets Have Moons

May 19, 2017 by  
Filed under Around The Net

While we know of thousands of exoplanets and exoplanet candidates, the search for moons outside of our solar system is just beginning. We don’t have a confirmed exomoon discovery yet, but they’re bound to be out there.

Finding exomoons will help us better understand habitability on Earth. Some experts say a reason that life arose is our own moon is so close to the size of our planet, which stabilized its axis rotation. However, other studies (such as this 2011 American Astronomical Society paper quoted in a NASA Astrobiology story) argue that the gravitational influence of other planets in our solar system provide enough stability.

A new study looks at the possibilities of large moons in TRAPPIST-1, a notoriously crowded exoplanet system that may have habitable planets within it. Earlier this year, observations from NASA’s Spitzer Space Telescope indicated that seven planets here could be rocky and have liquid water on their surfaces, making TRAPPIST-1 the system with the most potentially habitable planets.

But even before NASA’s discovery, TRAPPIST-1 was known and pondered by scientists, including the author of the new paper, Stephen Kane, an associate professor of astronomy at San Francisco State University who specializes in exoplanets.

“I have several publications now on exomoons, and for many years I’ve been thinking about how the ability of a planet to host a moon scales with the presence of nearby planets and proximity to the host star,” Kane said in an e-mail. “The discovery of the TRAPPIST-1 system prompted me to finally calculate whether or not planets in compact planetary systems can actually harbor moons.”

Kane cautioned that scientists can’t overly attribute Earth’s habitability to our moon, because Earth is the only known habitable planet. However, the moon does have an important role: It creates significant tides on Earth, which probably helped create the tidal pools in which early biochemistry could occur.

“The presence of the moon has helped to stabilize changes in the tilt of the Earth’s rotational axis, which in turn creates longer periods of climate stability,” Kane added. “So although it’s difficult to say what the Earth would be like without a moon, we can certainly describe ways in which it has positively influenced our present environment.”

For TRAPPIST-1, Kane found that the planets are so tightly packed together that large moons would likely be impossible. While the rotational axes of the planets would quickly change and have more chaotic climates, he said, life could still evolve — it just might take a longer time.

Kane’s methodology involved studying the influences of two parameters: the Hill radius, or the area in space in which a planet exerts gravitational influence based on its mass and distance from the host star, and the Roche limit, which identifies where the gravitational effect near a planet is too strong for a moon to survive.

“A moon can only exist around a planet if it lies between these two boundaries: too close and it will be destroyed, too far away and it will escape the gravitational influence of the planet,” Kane said. “The results of the study described in my paper show that, for most planets in compact planetary systems, the Hill radius and Roche limit are close enough to each other that there is no space in which a moon can exist and so such planets cannot have moons in orbit around them.”

Courtesy-Space

Is Another Mission To Pluto Warrented

May 18, 2017 by  
Filed under Around The Net

Humanity’s first up-close look at Pluto was so intriguing that some researchers want to go back and spend a lot more time studying the icy world.

Late last month, 35 scientists met for 7 hours in Houston to discuss the basic blueprint and science goals of a potential Pluto orbiter mission. Such an effort would build upon the knowledge gained during the epic Pluto flyby performed in July 2015 by NASA’s New Horizons probe.

Participants came away from the April 24 workshop fired up and committed to doing their best to make such a project happen, said New Horizons principal investigator Alan Stern, who was there.

The meeting was reminiscent, Stern said, of New Horizons’ earliest days: the late 1980s, when he and a few other people first raised the possibility of launching a flyby mission to Pluto.

“It felt a lot like that, but [with] a new generation of people,” Stern, who’s based at the Southwest Research Institute in Boulder, Colorado, told Space.com.

New Horizons’ flyby revealed Pluto to be a stunningly diverse world with vast plains of nitrogen ice, 2-mile-high (3.2 kilometers) mountains of water ice and a wealth of other surface features. But the probe got just a fleeting look at the dwarf planet system while zooming by; an orbiter would linger and lift Pluto’s veil even more, Stern said.

“You could map every square inch of the planet and its moons,” he said. “It would be a scientific spectacular.”

As the possible mission is currently envisioned, the orbiter would cruise around the Pluto system, using gravity assists from the dwarf planet’s largest moon, Charon, to slingshot it here and there, Stern said. The strategy would be similar to that employed by NASA’s Cassini spacecraft, which has shaped its path through the Saturn system over the years via flybys of the ringed planet’s largest moon, Titan.

The current concept is therefore different from one Stern proposed shortly after New Horizons’ flyby, which would have put a lander down on Charon.

With a Charon lander, “you’re stuck looking at one side of Pluto,” Stern said. (Charon and Pluto are tidally locked, meaning each world always shows the same face to the other.)

“And you can’t get in superclose. You can’t get down in the atmosphere,” he added. “This, I think, is a better mission concept.”

Though the mission would be Cassini-like, the Pluto orbiter itself would resemble NASA’s Dawn probe, which is currently circling the dwarf planet Ceres, Stern said. Like Dawn, the Pluto probe would likely use electric propulsion and have a half-dozen science instruments, he said.

 

However, because the Pluto orbiter would be operating so far from the sun, it would rely on nuclear power to generate its electricity, rather than sunlight, as Dawn does, Stern added. And the price tag would be higher than Dawn’s $467 million; the Pluto effort would probably qualify as a New Frontiers mission or a small flagship. (New Frontiers missions cost about $1 billion, whereas flagships run about $2 billion.)

Stern said a Pluto orbiter could get off the ground in the late 2020s or so. A 2030 launch would have ceremonial significance, coming on the 100th anniversary of Pluto’s discovery, he added. The probe would spend seven or eight years journeying to the dwarf planet, then perhaps four or five years studying Pluto and its moons.

When the probe’s work there was done, Stern said, the spacecraft could conceivably use one last Charon flyby to escape the Pluto system and head toward another object in the Kuiper Belt, the ring of frigid bodies beyond Neptune’s orbit. (New Horizons is doing something similar; it’s now headed for a Jan. 1, 2019, flyby of a small Kuiper Belt object called 2014 MU69.)

But a Pluto orbiter mission is a long way from becoming reality, Stern stressed. He said he and his fellow researchers aim to mature the concept in time for it to be considered during the next Planetary Science Decadal Survey, a U.S. National Research Council effort that sets exploration priorities for NASA every 10 years.

The next decadal survey will start in 2020, finish in 2022 and be published in 2023, Stern said.

“The curtain is opening,” he said of the Pluto orbiter idea. “This thing is going to be a topic of discussion now for the next few years.”

Courtesy-Space

Is Ridley Scott Right About An Alien Encounter

May 16, 2017 by  
Filed under Around The Net

Film director Ridley Scott, who delights in terrifying moviegoers with his cinematic blend of horror and science fiction, suggested in a recent interview that the scary prospect of belligerent invading aliens might transcend the realm of sci-fi. According to Scott, hundreds of alien species are “out there” on distant worlds, and Earth’s inhabitants should prepare for the worst if they ever decide to visit our planet.

One scientist, though, says that Scott’s information about such hostile, and abundant, aliens is off-base and unsupported.

Scott told Agence France-Presse (AFP) about his belief in “superior beings,” while fielding questions about his latest movie, “Alien: Covenant,” opening in theaters in the U.S. on May 19. He warned that any extraterrestrial travelers who are technologically advanced enough to show up on our doorstep would likely be very intelligent and very hostile. And unlike the scenarios that dominate movies — if we go toe-to-toe with these invaders, we probably won’t be the victors, he said.

“If you are stupid enough to challenge them you will be taken out in three seconds,” Scott told AFP. [Greetings, Earthlings! 8 Ways Aliens Could Contact Us]

In the interview, Scott explained that “the experts” estimate there are “between 100 and 200 entities” on other planets, following what could be a similar evolutionary path to ours. And if they get here first, our best bet would be to “run for it,” AFP reported.

The possibility of intelligent, technologically adept alien life has intrigued science-fiction writers and readers since the French writer Voltaire published his short story “Micromégas” in 1752, describing two extraterrestrial visitors to Earth — one from the planet Saturn and one from a planet orbiting the star Sirius.

Scott has made his own contributions to the genre, most notably with his string of “Alien” movies, which imagine a highly adaptable and morphologically flexible alien species. The so-called xenomorphs breed quickly and are ruthlessly efficient at overpowering humans, either swiftly dismembering them or cultivating them as hosts for their young — luckily, in isolated locations that are far from our home planet.

But though Scott is a skilled sci-fi yarn-spinner, his assessment of real-world alien threats could use a script doctor, according to Seth Shostak, senior astronomer with the SETI Institute, a research institution dedicated to the search for communication signals produced by intelligent extraterrestrial life.

To begin with, Scott’s “expert” estimate of 100 to 200 “entities” is entirely unsubstantiated, Shostak told Live Science.

“We have absolutely no data that would tell you what that number might be,” he said.

In fact, estimates based on data about known planets and galaxies suggest that the actual number of intelligent extraterrestrial life forms could, in fact, be significantly higher. With approximately 1 trillion planets in our galaxy alone, and about 2 trillion more galaxies, that adds up to…well, it’s a lot of planets, Shostak said.

To narrow the search a bit, scientists could start by just looking at the trillion planets in our own galaxy, he said. Only a fraction of those planets might be capable of supporting life — perhaps 1 in 10. And maybe only 1 in 1,000 could produce and support life more complex than bacteria, he said.

That gives us about a billion planets in our galaxy that might harbor some type of intelligent life. But over time, life on many of those planets could have already waxed and waned — self-destructed or been wiped out. Perhaps only one planet in a million of those intelligent-life-harboring worlds still support life capable of contacting humans. That adds up to about 1,000 planets that could potentially hold intelligent, extraterrestrial species, Shostak told Live Science.

However, if a planet is more than 70 light-years from Earth, it hasn’t yet received any radio signals from us. Its residents, no matter how technologically adept, wouldn’t know humans exist yet. Even if long-distance observations of Earth told them we had oxygen in our atmosphere — and thereby some form of life — they’d be very unlikely to travel all this way to look at what might amount to just a lot of bacteria, Shostak added. 

Neither would extraterrestrials be likely to invade our solar system merely to steal our resources, he said. If a civilization is advanced enough that they’ve exhausted all the resources of their entire star system — every planet, moon and asteroid — and are all out of natural materials, they’re probably at a stage where they could create what they needed from simpler materials in their own backyard, rather than traveling across the galaxy for a very limited supply, Shostak said.

It’s equally unlikely they’d be showing up because they thought humans would make an excellent addition to their diet, he said.

“To do that, they would have to know that we had something interesting within our bodies that they could metabolize, and their body chemistry would probably be very different from ours,” Shostak said.

But Scott did get one thing right: If extraterrestrials are capable of building spacecraft that can transport them to our planet, they certainly would be technologically “superior” to people, Shostak said. And if he saw a spaceship suddenly appear, Shostak admitted that he’d probably do as Scott suggested — and just “run for it.”

Courtesy-Space

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