According to New Findings, Subsurface Life On Mars Was Once Possible Reply

See on Scoop.itScience Communication from mdashf

McLaughlin Crater is 90.92 km (56.50 mi) in diameter and 2.2 km (1.4 mi) deep with a floor that is well below Martian “sealevel” and contains clays that bear iron and magnesium as well as carbonate.

 

By the time eukaryotic life or photosynthesis evolved on Earth, the martian surface had become extremely inhospitable, but the subsurface of Mars could potentially have contained a vast microbial biosphere. Crustal fluids may have welled up from the subsurface to alter and cement surface sediments, potentially preserving clues to subsurface habitability. Many ancient, deep basins lack evidence for groundwater activity. However, McLaughlin Crater, one of the deepest craters on Mars, contains evidence for Mg–Fe-bearing clays and carbonates that probably formed in an alkaline, groundwater-fed lacustrine setting. This environment strongly contrasts with the acidic, water-limited environments implied by the presence of sulphate deposits that have previously been suggested to form owing to groundwater upwelling. Deposits formed as a result of groundwater upwelling on Mars, such as those in McLaughlin Crater, could preserve critical evidence of a deep biosphere on Mars. Scientists suggest that groundwater upwelling on Mars may have occurred sporadically on local scales, rather than at regional or global scales.

 

“This environment strongly contrasts with the acidic, water-limited environments implied by the presence of sulphate deposits that have previously been suggested to form owing to groundwater upwelling.”

 

Water-made channels which are now dry, appear to flow down the walls of McLaughlin Crater and stop well above the crater floor, which indicates they once provided water to a lake. “The deposits in McLaughlin Crater could have very high preservation potential for organic materials, in much the same manner as turbidites do on Earth.”

 

Cyanobacteria, which are common in alkaline lakes on Earth may have aided in the formation of carbonate minerals in lakes such as the McLAughlin Crater on Mars. Sometimes these bacteria become form microscopic fossils. If similar conditions existed in the craters ancient alkaline lake fossils of micro-organisms may still be there awaiting us.

See on spaceindustrynews.com

First evidence for extraterrestrial life might come from dying stars Reply

See on Scoop.itScience Communication from mdashf

Even dying stars could host planets with life—and if such life exists, we might be able to detect it within the next decade. This encouraging result comes from a new theoretical study of Earth-like planets orbiting white dwarf stars. Researchers found that we could detect oxygen in the atmosphere of a white dwarf’s planet much more easily than for an Earth-like planet orbiting a Sun-like star.

“In the quest for extraterrestrial biological signatures, the first stars we study should be white dwarfs,” said Avi Loeb, theorist at the Harvard-Smithsonian Center for Astrophysics (CfA) and director of the Institute for Theory and Computation.

 

When a star like the Sun dies, it puffs off its outer layers, leaving behind a hot core called a white dwarf. A typical white dwarf is about the size of Earth. It slowly cools and fades over time, but it can retain heat long enough to warm a nearby world for billions of years.

 

Since a white dwarf is much smaller and fainter than the Sun, a planet would have to be much closer in to be habitable with liquid water on its surface. A habitable planet would circle the white dwarf once every 10 hours at a distance of about a million miles.

 

Before a star becomes a white dwarf it swells into a red giant, engulfing and destroying any nearby planets. Therefore, a planet would have to arrive in the habitable zone after the star evolved into a white dwarf. A planet could form from leftover dust and gas (making it a second-generation world), or migrate inward from a larger distance.

 

If planets exist in the habitable zones of white dwarfs, we would need to find them before we could study them. The abundance of heavy elements on the surface of white dwarfs suggests that a significant fraction of them have rocky planets. Loeb and his colleague Dan Maoz (Tel Aviv University) estimate that a survey of the 500 closest white dwarfs could spot one or more habitable Earths.

 

The best method for finding such planets is a transit search – looking for a star that dims as an orbiting planet crosses in front of it. Since a white dwarf is about the same size as Earth, an Earth-sized planet would block a large fraction of its light and create an obvious signal.

 

More importantly, we can only study the atmospheres of transiting planets. When the white dwarf’s light shines through the ring of air that surrounds the planet’s silhouetted disk, the atmosphere absorbs some starlight. This leaves chemical fingerprints showing whether that air contains water vapor, or even signatures of life, such as oxygen.

See on phys.org

Space-based solar farms would solve mankind’s energy needs overnight, but there are huge technical hurdles Reply

See on Scoop.itScience Communication from mdashf

“Ex-Nasa scientist seeks visionary billionaire to help change the world.  High risk venture. Return not guaranteed. GSOH a plus.”

 

John Mankins, the scientist in question, has not yet reached the point of placing a classified ad, but it could soon be an option. The 25-year veteran of the US space agency is the man behind a project called SPS-Alpha, which aims to loft tens of thousands of lightweight, inflatable modules into space. Once there, they will be assembled into a huge bell-shaped structure that will use mirrors to concentrate energy from the sun onto solar panels. The collected energy would then be beamed down to ground stations on Earth using microwaves, providing unlimited, clean energy and overnight reducing our reliance on polluting fossil fuels. The snag? It is unproven technology and he estimates it will take at least $15 B – $20 B to get his project off the ground.

 

Mankins initially had research funding from an advanced concepts arm at Nasa, but that money dried up in September 2012; hence his continuing search for a benefactor. “I can’t think of a better solution than to find somebody who is very wealthy, very visionary and willing to make this happen,” he says.

 

But not everyone shares Mankins’ optimism. Space-based solar power (SBSP) is a topic that divides the scientific world into extremes. On one side are people like Mankins who believe it is the only solution to our ever increasing energy demands, whilst on the other is a sizeable chunk of the scientific community who believe any money put into solar power should remain firmly on the ground.

 

SBSP has its roots in the 1941 short story Reason, by Isaac Asimov, which depicts a space station – run by robots – collecting energy from the sun to distribute to Earth and other planets. No further thought was given to the idea until the late 1960s, when aerospace engineer Peter Glaser began to investigate its potential. In the following decades, various concepts were put forward but none took off. At the same timeNasa and the US Department of Energy also became involved, funding bits and pieces of research and commissioning reports into its feasibility. Most of these concluded that SBSP was too “high risk” and too costly.

 

But in recent years, SBSP has once again begun to attract attention with projects emerging in the US, Russia, China, India and Japan, amongst others. All are driven by increasing energy demands, soaring oil and gas prices, a desire to find clean alternatives to fossil fuels and by a burgeoning commercial space industry that promises to lower the cost of entry into space and spur on a host of new industries.

 

“SBSP is the ultimate energy source for the world and eventually it’s going to replace nearly everything else,” says Ralph Nansen of US-based advocacy group Solar High, with some of the characteristic hyperbole that defines both sides of the SBSP debate. “I don’t think there’s any doubt that within the next century we will be getting the majority of our power from space. It’s just a question of when.”

See on www.bbc.com

For the first time ever, astrophysicists have reliably measured the spinning speed of a supermassive black hole Reply

See on Scoop.itScience Communication from mdashf

A team of scientists led by Harvard astronomer Guido Risaliti recounts its findings in the latest issue of Nature. The researchers accomplished the feat by measuring electromagnetic radiation emanating from the center of spiral galaxy NGC 1365. There — not unlike the center of our own Milky Way — a spherical region of spacetime more than 2 million miles in diameter whirls violently, its gravity so strong it actually schleps surrounding space along with it. Any matter that trespasses beyond the black hole’s event horizon spirals inward and collects in what’s known as an accretion disc, where it is subjected to so much friction it emits X-rays.

 

Thanks to a joint effort by the ESA’s XMM-Newton and NASA’s recently launched NuSTAR (both X-ray observatories, positioned in Earth orbit), Risaliti and his colleagues were able to locate the inner boundary of the accretion disc. Sometimes known as the Innermost Stable Circular Orbit, the position of this accretion disc “edge” depends on the speed of the black hole’s overall rotation. The astronomers used this relationship to calculate the spin rate of the black hole’s surface, which they estimate is is traveling at nearly the speed of light — about 84% as fast, to be exact.

 

In a statement, Risaliti says that it is “the first time anyone has accurately measured the spin of a supermassive black hole,” but insists that even more important is what his team’s findings can tell us about this black hole’s past, and the developmental history of its surrounding galaxy.

 

The spin of a black hole is thought to be affected by the way it pulls in matter. It stands to reason, for example, that a black hole that subsumes gas and stars at random is more likely to fetter its angular momentum than add to it. According to Risaliti and his team, that the supermassive black hole at the center of NGC 1365 is spinning at speeds approaching the cosmic speed limit would suggest it acquired mass through ordered accretion, as opposed to multiple random events.

 

For more details, visit SPACE.com, where Mike Wall has a great overview of the role that NASA’s NuSTAR (launched in July of last year) has played in resolving a longstanding debate over the implications of X-ray emission patterns emanating from black holes.

 

“It’s the first time that we can really say that black holes are spinning,” said study co-author Fiona Harrison in an interview with Wall. “The promise that this holds for being able to understand how black holes grow is, I think, the major implication.”

See on io9.com

Is This a Baby Picture of a Giant Proto Planet? Reply

See on Scoop.itScience Communication from mdashf

Acquired by the European Southern Observatory’s Very Large Telescope (VLT), the infrared image above (right) shows a portion of the disk of gas and dust around the star HD100546, located 335 light-years away in the constellation Musca. By physically blocking out the light from the star itself by means of an opaque screen — seen along the left side of the image — the light from the protoplanetary disk around HD 100546 can be seen, revealing a large bright clump that’s thought to be a planet in the process of formation.

 

If it is indeed a baby planet, it’s a big one — as large as, or perhaps even larger than, Jupiter. A candidate protoplanet found in a disc of gas and dust around young star HD100546 (ESO).

 

This does raise an interesting question for astronomers because if itis a Jupiter-sized planet, it’s awfully far from its star… at least according to many current models of planetary formation. About 68 times as far from HD100546 as we are from the sun, if this planet were in our solar system it’d be located deep in the Kuiper Belt, twice as far as Pluto. That’s not where one would typically expect to find gas giants, so it’s been hypothesized that this protoplanet might have migrated outwards after initially forming closer to the star… perhaps “kicked out” by gravitational interaction with an even more massive planet.

 

 

See on news.discovery.com

Space Impact Prevention: Russia Calls for United Meteor Defense System Reply

See on Scoop.itScience Communication from mdashf

The world should unite to establish a defense system against space objects that threaten Earth, Russian Deputy Prime Minister Dmitry Rogozin says.

Rogozin, speaking Saturday at a ceremony marking Defender of the Fatherland Day in the Moscow suburb of Krasnogorsk, told members of his Rodina Party the effort should be undertaken under the umbrella of the United Nations, RIA Novosti reported.

 

The Russian leader said the threat from asteroids, meteorites, comets and other stray space objects should serve to “unite humanity in the face of a common enemy.” “This system should become global and universal in its technical and political sense and is a matter of agreement in the framework of the United Nations,” Rogozin said.

 

The call came as Russia is recovering from a Feb. 15 meteorite strike near Chelyabinsk in the Ural Mountains region that created a massive shock, blowing out windows, damaging thousands of buildings and injuring 1,200 people, mainly from flying glass.

 

More than 50 people were hospitalized and damage from the shock wave has been estimated at $33 million. Creating an effective protection against stray space objects is a task that no country, including the United States, would be able to be able to cope with alone, Rogozin said, asserting that no one system of aerospace defense on the planet could handle the threat.

 

The problem with current anti-missile systems and other aerospace defense technologies is that they’re designed to track incoming objects launched from the ground, rather than those coming from space, Rogozin said.

 

To protect against such “cosmic enemies,” he said, the world would need a system able to recognize the risk in advance. “The great space powers, including Russia, could make in-kind contributions with the technology and programs that have already been established,” he said.

 

“We need to find such technical decisions, which we don’t have now, such capabilities which could change the flight path of a dangerous space object at a long distance from the Earth or destroy it.”

 

However, Rogozin added, if such a worldwide anti-asteroid system were to be established, some countries could use it as a pretext to deploy nuclear weapons in space, Interfax reported.

 

“An undesirable effect of this might be that, under the guise of countering asteroids, some countries, which I prefer not to name, might use this as a pretext for deploying nuclear weapons in outer space,” he said.

 

Alexander Bagrov, a senior researcher at the Institute of Astronomy of the Russian Academy of Sciences, told the Voice of Russia such a worldwide defense system against space objects can be created.

See on www.spacedaily.com