Posts Tagged ‘asteroid’

The ancestors of modern birds may have survived the asteroid strike that wiped out the rest of their kin by living on the forest floor.

The new theory, based on studying fossilised plants and ornithological data, helps explain how birds came to dominate the planet.

The asteroid impact 66 million years ago laid waste to the world’s forests.

Ground-dwelling bird ancestors managed to survive, eventually taking to the trees when the flora recovered.

“It seems clear that being a relatively small-bodied bird capable of surviving in a tree-less world would have conferred a major survival advantage in the aftermath of the asteroid strike,” said Dr Daniel Field of the Milner Centre for Evolution at the University of Bath.

We already know that the early ancestors of modern birds were probably capable of flight, and relatively small in size.

Scientists have now pieced together their ecology to better understand how these partridge-like bird ancestors managed to avoid destruction in a particularly bleak moment in the Earth’s history.

“Teasing these stories from the rock record is a challenge when the action took place over 66 million years ago, over a relatively short period of time,” said Dr Field, who led a team of UK, US and Swedish researchers.

The plant fossil record shows that the asteroid caused global deforestation and extinction of most flowering plants, destroying the habitats of tree-dwelling animals.

Birds didn’t move back into the trees again until the forests recovered thousands of years later.

“The recovery of canopy-forming trees such as palms and pines happened much later, which coincides with the evolution and explosion of diversity of tree-dwelling birds,” said Dr Antoine Bercovici from Smithsonian Institution.

The researchers found that once the forests had recovered, birds began to adapt to living in trees, acquiring shorter legs than their ground-dwelling ancestors and various specialisations for perching on branches.

They eventually diversified into ostriches and their relatives, chickens and their relatives, and ducks and their relatives.

“Perhaps the best modern analogue for one of the surviving birds lineages are modern tinamous – this is a modern group of flying relatives of ostriches: they are relatively small bodied, and live on the ground,” said Dr Field.

Today’s “amazing living bird diversity can be traced to these ancient survivors”, he added.

The research is published in the journal Current Biology.

http://www.bbc.com/news/science-environment-44226534

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By Rafi Letzter

Russian scientists have a plan to deal with a hypothetical asteroid threat that’s straight out of the movie “Armageddon.”

A team of government scientists has proposed that nuclear weapons well within the power of those already developed could be used to break up incoming asteroids, protecting the planet from a major asteroid strike. They then demonstrated, in a paper published online March 8 in the Journal of Experimental and Theoretical Physics, the effect of a nuclear strike on an asteroid, using scale model “asteroids” and powerful lasers.

Striking a tiny model asteroid with a powerful laser on Earth is obviously not the exact same thing as striking a full-size asteroid with a laser out in space. But there’s a reasonable degree of comparison between the two situations.

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Russian Scientists Tested Their Asteroid-Nuking Plan with Powerful Lasers
This photo of the asteroid Eros was taken during the NEAR Shoemaker mission.
Credit: NASA
Russian scientists have a plan to deal with a hypothetical asteroid threat that’s straight out of the movie “Armageddon.”

A team of government scientists has proposed that nuclear weapons well within the power of those already developed could be used to break up incoming asteroids, protecting the planet from a major asteroid strike. They then demonstrated, in a paper published online March 8 in the Journal of Experimental and Theoretical Physics, the effect of a nuclear strike on an asteroid, using scale model “asteroids” and powerful lasers.

Striking a tiny model asteroid with a powerful laser on Earth is obviously not the exact same thing as striking a full-size asteroid with a laser out in space. But there’s a reasonable degree of comparison between the two situations. [Crash! The 10 Biggest Impact Craters on Earth]

The researchers took careful steps to make sure the scale models were created from the same materials and had similar structures to chondrites (common, stony asteroids). And the immense energy deposited by a pulsed laser onto a single point on the model was reasonably similar to the effect of a nuclear blast on a single point on the asteroid’s surface. They wrote that their experiment showed they could use a a 3-megaton bomb to blast a 656-foot-wide (200 meters) asteroid — 10 times wider than the asteroid that detonated over Russia in 2013 — to harmless bits that would spread out and miss Earth.

The first thermonuclear weapon ever detonated had a strength of about 10.4 megatons, according to the Nuclear Weapon Archive. That bomb was detonated on Elugelab Island, Enewetak Atoll, in the Pacific Ocean in 1952.

There are other methods for diverting incoming asteroids, the researchers acknowledged, like the gravity tug— using the force of gravity to move the space rock to a better orbit. But they require more advanced knowledge of the incoming strike and planning. The advantage of a nuclear strike, they wrote, is that it can work against even surprise asteroids discovered late.

Russia isn’t alone in considering the possibility of a nuclear strike on an asteroid. U.S. government researchers also raised the possibility in a February paper.

https://www.livescience.com/62057-asteroid-nuclear-bomb-russia-laser.html?utm_source=notification

By Paul Rincon

The first known interstellar asteroid may hold water from another star system in its interior, according to a study.

Discovered on 19 October, the object’s speed and trajectory strongly suggested it originated beyond our Solar System.

The body showed no signs of “outgassing” as it approached the Sun, strengthening the idea that it held little if any water-ice.

But the latest findings suggest water might be trapped under a thick, carbon-rich coating on its surface.

The results come as a project to search for life in the cosmos has been using a radio telescope to check for radio signals coming from the strange, elongated object, named ‘Oumuamua.’

Astronomers from the Breakthrough Listen initiative have been looking across four different radio frequency bands for anything that might resemble a signal resulting from alien technology.

But their preliminary results have drawn a blank. The latest research – along with a previous academic paper – support a natural origin for the cosmic interloper.

Furthermore, they measured the way that ‘Oumuamua reflects sunlight and found it similar to icy objects from our own Solar System that are covered with a dry crust.

“We’ve got high signal-to-noise spectra (the ‘fingerprint’ of light reflected or emitted by the asteroid) both at optical wavelengths and at infrared wavelengths. Putting those together is crucial,” Prof Alan Fitzsimmons, from Queen’s University Belfast (QUB), one of the authors of the new study in Nature Astronomy.

He added: “What we do know is that the spectra don’t look like something artificial.”

Their measurements suggest that millions of years of exposure to cosmic rays have created an insulating, carbon-rich layer on the outside that could have shielded an icy interior from its encounter with the Sun.

This process of irradiation has left it with a somewhat reddish hue, similar to objects encountered in the frozen outer reaches of our Solar System.

“When it was near the Sun, the surface would have been 300C (600 Kelvin), but half a metre or more beneath the surface, the ice could have remained,” Prof Fitzsimmons told BBC News.

Previous measurements suggest the object is at least 10 times longer than it is wide. That ratio is more extreme than that of any asteroid or comet ever observed in our Solar System. Uncertainties remain as to its size, but it is thought to be at least 400m long.

“We don’t know its mass and so it could still be fragile and have a relatively low density,” said Prof Fitzsimmons.

“That would still be consistent with the rate at which it is spinning – which is about once every seven-and-a-half hours or so. Something with the strength of talcum powder would hold itself together at that speed.”

Molten core

He added: “It’s entirely consistent with cometary bodies we’ve studied – with the Rosetta probe, for example – in our own Solar System.”

Co-author Dr Michele Bannister, also from QUB, commented: “We’ve discovered that this is a planetesimal with a well-baked crust that looks a lot like the tiniest worlds in the outer regions of our Solar System, has a greyish/red surface and is highly elongated, probably about the size and shape of the Gherkin skyscraper in London.

“It’s fascinating that the first interstellar object discovered looks so much like a tiny world from our own home system. This suggests that the way our planets and asteroids formed has a lot of kinship to the systems around other stars.”

A number of ideas have been discussed to explain the unusual shape of ‘Oumuamua. These include the possibility that it could be composed of separate objects that joined together, that a collision between two bodies with molten cores ejected rock that then froze in an elongated shape, and that it is a shard of a bigger object destroyed in a supernova.

In a paper recently published on the Arxiv pre-print server, Gábor Domokos, from the Budapest University of Technology in Hungary, and colleagues suggest that, over millions of years, collisions between ‘Oumuamua and many speeding interstellar dust grains could produce the object’s observed shape.

Prof Fitzsimmons said this idea was very interesting, and added: “I think what we’re looking at here is the initial flurry of scientists running around saying: ‘How did it get like this, where’s it come from, what’s it made of.’ It’s incredibly exciting.

“I think after a few months you will see people focus down on one or two possibilities for all these things. But this just shows you: it’s a symptom of what an amazing, interesting object this is… we can’t wait for the next one.”

If planets form around other stars the same way they did in the Solar System, many objects the size of ‘Oumuamua should get slung out into space. The interstellar visitor may provide the first evidence of that process.

“All the data we have at the moment turn out to be consistent with what we might expect from an object ejected by another star,” he said.

But asked about Breakthrough Listen’s initiative, he said: “If I had a radio telescope, I might give it a go.”

http://www.bbc.com/news/science-environment-42397398

It’s a preemptive move to be sure, but when we are finally able to mine valuable resources from asteroids, rest assured that it’s fully legal to keep what you find. On Thursday, President Obama signed the U.S. Commercial Space Launch Competitiveness Act into law, which grants companies the rights to whatever they manage to pluck out of these extraterrestrial bodies. Effectively an extension of capitalism into space, the bill is one of the few during Obama’s presidency that received widespread support from the GOP, because apparently, nothing screams bipartisanship like asteroid mining.

Calling it “bipartisan, bicameral legislation,” Congressman Bill Posey of Florida called the law “a landmark for American leadership in space exploration.” A far departure from the 1967 Outer Space Treaty, which banned countries from “claiming or appropriating any celestial resource such as the Moon or another planet,” the new act paves the way for what some say could eventually become a multi-trillion dollar industry. Some estimates suggest that platinum filled asteroids could be worth as much as $50 billion. Unfortunately, the technology to take advantage of these resources does not yet exist.

This certainly hasn’t stopped the praise from rolling in, however. “This is the single greatest recognition of property rights in history,” said Eric Anderson, Co-Founder and Co-Chairman, Planetary Resources, Inc. “This legislation establishes the same supportive framework that created the great economies of history, and will encourage the sustained development of space.” Of course, the law doesn’t mean that anyone can lay claim to an entire celestial body (sticking a flag in something doesn’t make it yours), but now, individuals or corporations can claim property rights to whatever is found on these bodies.

In addition to its stance on asteroid mining, the bill also reaffirms and the United States’ role in the maintenance of the International Space Station. Whereas previous agreements necessitated American involvement until 2020, this latest bill requires that U.S. astronauts play a major role in ISS “through at least 2024.”

And furthermore, to ensure that more SpaceX type projects can emerge (and compete with China’s growing space program), the law also loosens regulations on space startups, allowing them greater freedoms in certain operations.

“Throughout our entire economy, we need to eliminate unnecessary regulations that cost too much and make it harder for American innovators to create jobs,” said presidential candidate Marco Rubio. “The reforms included here make it easier for our innovators to return Americans to suborbital space and will help the American space industry continue pushing further into space than ever before.”

Read more: http://www.digitaltrends.com/cool-tech/commercial-space-launch-competetiveness-act-2015-asteroid-mining/#ixzz3suQKzAKF