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Showing posts with label EARTH. Show all posts
Showing posts with label EARTH. Show all posts

Wednesday 22 July 2015

NEW NASA CAMERA PROVIDES AN ‘EPIC’ VIEW OF EARTH

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This is what Earth looks like from a million miles away.
The stunning image, which focuses on America, was taken by the Deep Space Climate Observatory (DSCOVR) and is the satellite’s first view of the entire sunlit side of our planet.
It was presented to the White House today, prompting a tweet from President Barack Obama describing it as: ‘A beautiful reminder that we need to protect the only planet we have.’
The blue marble was captured by the Earth Polychromatic Imaging Camera (Epic) and created by combining three separate images to show the Earth in incredible detail.
The camera takes a series of 10 images using different narrowband filters – from ultraviolet to near infrared.
‘This first DSCOVR image of our planet demonstrates the unique and important benefits of Earth observation from space,’ said Nasa Administrator Charlie Bolden.
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DSCOVR orbits the sun at a location called the Lagrange point 1, or L1, It’s from that unique vantage point that the Epic instrument is acquiring science quality images of the entire sunlit face of Earth. Data from Epic will be used to measure ozone and aerosol levels in Earth’s atmosphere, cloud height, vegetation properties and the ultraviolet reflectivity of Earth

Thursday 13 November 2014

The Rosetta comet landing has made history

http://i.telegraph.co.uk/multimedia/archive/02758/Rosetta_2758749b.jpg

After 10 years of hard work and one nerve-wracking night, the Rosetta mission has made history by landing on the surface of a comet.

The lander Philae was confirmed to touch down on the surface of the comet more than 300 million miles away at 11:03 a.m. Eastern. Now, scientists expect it to send a panoramic image home and begin analyzing the comet for scientists back on Earth.

Philae is already transmitting scientific data back home, but we're still waiting to see whether the probe is in a stable position. Until we know it's anchored tight, it could roll onto its back and never get back up.

Tensions were high in the European Space Agency's German mission control center, especially as the landing window approached. Because the comet that Philae landed on is so far from Earth, there's a communications delay of 28 minutes. So as the minutes ticked by, the Rosetta team knew that Philae had already either landed or failed — and there was nothing they could do but wait for the data to reach them. Those following the video online were nearly as desperate for news, and Twitter became a sounding chamber of anticipation and excitement.

But a few minutes after 11 a.m., the stern, cautious expressions of the mission control team melted into smiles. And just like that, the world swiveled from anxiety to elation: Philae was on the surface of the comet and ready to do some science.

The comet contains the materials that originally formed our solar system, frozen in time. By digging them out, we can learn more about the origins of our planet. The Rosetta spacecraft has made invaluable observations about the comet's attributes, and it will continue to do so as it follows it around the sun for the next year. But Philae will be able to look more closely at the comet's physical and molecular composition.

"It's a look at the basic building blocks of our solar system, the ancient materials from which life emerged," said Kathrin Altwegg of the University of Bern in Switzerland, one of the Rosetta project's lead researchers. "It's like doing archaeology, but instead of going back 1,000 years, we can go back 4.6 billion."

It's no easy thing to land on a comet's surface: These chunks of rock and ice are constantly spinning, and Comet 67P/Churyumov-Gerasimenko, which was discovered in 1969, orbits the sun at a speed of about 85,000 mph. It's irregularly shaped — like a toddler's play-dough impression of a duck, or something — and its surface is uneven and pitted. And in a universe of unimaginable proportion, Rosetta's target is just 2.5 miles in diameter — smaller than Northwest Washington's Columbia Heights neighborhood.

So Rosetta has taken an onerous journey to get in sync with the comet's orbit, which would allow it to drop down a lander. In 2004, the spacecraft began what would be three looping orbits around the sun, altering its trajectory as it skimmed Mars, just 150 miles from the surface, and enduring 24 minutes in the planet’s shadow to align with Churyumov-Gerasimenko. The cumulative distance traveled by the craft – with all its looping and gravity assists – is a stunning 4 billion miles. “When the Rosetta signal reappeared after the passage behind Mars, shortly after the end of the ‘shadow’ period, there was a collective sigh of relief,” ESA said.

At one point in 2011, the spacecraft even had to hibernate for nearly three years. It flew so far from the sun — nearly 500 million miles — that its solar panels couldn't leech enough energy to keep the spacecraft operational. But in January of this year, Rosetta woke up, and quickly approached its target.

The last leg of this landing has not been without its bumps. Even as the mission approached its most critical moment, controllers at the European Space Agency on Tuesday night reported a problem with the thruster on the lander that could make for a rough landing. The gravity of the problem — and the extent to which it threatened the mission — remained unknown. “We’ll need some luck not to land on a boulder or a steep slope,” blogged Stephan Ulamec, lander manager for the project.

Source : washington post

Saturday 8 November 2014

Is Earth the only technologically-intensive civilization in Universe?

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A new study has revealed that the combination of earth-based science of sustainability and the space-oriented field of astrobiology can shed light on the future of technological civilization on Earth and is the planet first and only technologically-intensive culture in Universe.
Human-caused climate change, ocean acidification and species extinctions may eventually threaten the collapse of civilization, according to some scientists, while other people argue that for political or economic reasons industrial development should be allowed without restrictions.

In the paper, two astrophysicists argue that these questions may soon be resolvable scientifically, thanks to new data about the Earth and about other planets in our galaxy, and by combining the earth-based science of sustainability with the space-oriented field of astrobiology .

Astrophysicists Adam Frank and Woodruff Sullivan call for creation of a new research program to answer questions about humanity's future in the broadest astronomical context.

The authors explained that the point would be to see that Earth's current situation might, in some sense, be natural or at least a natural and generic consequence of certain evolutionary pathways.

The researchers also showed that how habitability studies of exoplanets hold important lessons for sustaining the civilization we have developed on Earth.

According to the results, studying past extinction events and using theoretical tools to model the future evolutionary trajectory of humankind and of still unknown but plausible alien civilizations could inform decisions that would lead to a sustainable future.

Source : Zee news

Thursday 6 November 2014

Rosetta spacecraft set to land on Comet Churyumov-Gerasimenko

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An artist's impression of the Philae probe setting down on Comet Churyumov-Gerasimenko.

If you have an interest in space exploration, you could not have picked a better time in history to be alive than right now. Data and images stream back to Earth daily at an unprecedented rate from robotic spacecraft active at far-flung destinations all over the solar system. To use an old political quote – we've never had it so good.

In the past 50 years we've exploded out of our "little blue dot" to leave boot prints on the moon, land on Venus, Mars and Saturn's moon Titan, and to orbit Mercury, Jupiter, Saturn, asteroids and comets, giving us incredible visual vistas of all.

What's missing is a detailed view of dwarf planet Pluto, but we'll have that when the New Horizons spacecraft gets there next year.

There's also another missing first about to be achieved next week – we're going to make a soft landing on the surface of a comet.

Comet Churyumov-Gerasimenko had to wait around patiently for billions of years for humans to discover it in 1967. However, it's been a much shorter wait for an opportunity to get up close and personal with it – we're landing a probe on the frozen dumbbell-shaped comet next Wednesday, November 12.

The Rosetta spacecraft, carrying the Philae probe, was launched  from French Guiana in February 2004 by the European Space Agency. It arrived in August this year and has already given us great views of the comet.

It was named for the Rosetta Stone found in Egypt that was crucial in deciphering ancient Egyptian hieroglyphics. Similarly the "lander" is named for the Nile River island Philae, where an obelisk also assisted in solving the puzzle of these symbols.

Thursday 30 October 2014

Evidence Builds for Dark Matter Explosions at the Milky Way’s Core

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This Fermi map of the Milky Way center shows an overabundance of gamma-rays (red indicates the greatest number) that cannot be explained by conventional sources.

So far, dark matter has evaded scientists’ best attempts to find it. Astronomers know the invisible stuff dominates our universe and tugs gravitationally on regular matter, but they do not know what it is made of. Since 2009, however, suspicious gamma--ray light radiating from the Milky Way’s core—where dark matter is thought to be especially dense—has intrigued researchers. Some wonder if the rays might have been emitted in explosions caused by colliding particles of dark matter. Now a new gamma-ray signal, in combination with those already detected, offers further evidence that this might be the case.

One possible explanation for dark matter is that it is made of theorized “weakly interacting massive particles,” or WIMPs. Every WIMP is thought to be both matter and antimatter, so when two of them meet they should annihilate on contact, as matter and antimatter do. These blasts would create gamma-ray light, which is what astronomers see in abundance at the center of our galaxy in data from the Fermi Gamma-Ray Space Telescope. The explosions could also create cosmic-ray particles—high-energy electrons and positrons (the antimatter counterparts of electrons)—which would then speed out from the heart of the Milky Way and sometimes collide with particles of starlight, giving them a boost of energy that would bump them up into the gamma-ray range. For the first time scientists have now detected light that matches predictions for this second process, called inverse Compton scattering, which should produce gamma rays that are more spread out over space and come in a different range of energies than those released directly by dark matter annihilation.

“It looks pretty clear from their work that an additional inverse Compton component of gamma rays is present,” says Dan Hooper, an astrophysicist at the Fermi National Accelerator Laboratory who was not involved in the study, but who originally pointed out that a dark matter signal might be present in the Fermi telescope data. “Such a component could come from the same dark matter that makes the primary gamma-ray signal we've been talking about all of these years.” University of California, Irvine scientists Anna Kwa and Kevork Abazajian presented the new study October 23 at the Fifth International Fermi Symposium in Nagoya, Japan and submitted their paper to Physical Review Letters.

None of the intriguing gamma-ray light is a smoking gun for dark matter. Other astrophysical processes, such as spinning stars called pulsars, can create both types of signal. “You can make models that replicate all this with astrophysics,” Abazajian says. “But the case for dark matter is the easiest, and there’s more and more evidence that keeps piling up.”

The official Fermi telescope team has long been cautious about drawing conclusions on dark matter from their data. But at last week’s symposium, the group presented its own analysis of the unexplained gamma-ray light and concluded that although multiple hypotheses fit the data, dark matter fits best. “That’s huge news because it’s the first time they’ve acknowledged that,” Abazajian says. Simona Murgia, an astrophysicist at the University of California, Irvine and a member of the Fermi collaboration’s galactic-center analysis team, presented the team’s findings. She says the complexity of the galactic center makes it difficult to know for sure how the excess of gamma rays arose and whether or not the light could come from mundane “background” sources. “It is a very interesting claim,” she says of Abazajian’s analysis. “However, detection of extended excesses in this region of the sky is complicated by our incomplete understanding of the background.”

The dark matter interpretation would look more likely if astronomers could find similar evidence of WIMP annihilation in other galaxies, such as the two dozen or so dwarf galaxies that orbit the Milky Way. “Extraordinary claims require extraordinary evidence, and I think a convincing claim of discovery would probably require a corresponding signal in another location—or by a non-astrophysical experiment—as well as the galactic center,” says Massachusetts Institute of Technology astrophysicist Tracy Slatyer, who has also studied the Fermi data from the Milky Way’s center.

Non-astrophysical experiments include the handful of so-called direct-detection experiments on Earth, which aim to catch WIMPs on the extremely rare occasions when they bump into atoms of normal matter. So far, however, none of these has found any evidence for dark matter. Instead they have steadily whittled away at the tally of possible types of WIMPs that could exist.

Other orbiting experiments, such as the Alpha Magnetic Spectrometer (AMS) on the International Space Station, which detects cosmic rays, have also failed to find convincing proof of dark matter. In fact, the AMS results seem to conflict with the most basic explanations linking dark matter to the Fermi observations. “Most people would agree that there is something rather unexpected happening at the galactic center, and it would be tremendously exciting if it turns out to be a dark matter annihilation signal,” says Christoph Weniger of the University of Amsterdam, another astrophysicist who has studied the Milky Way’s core. “But we have to confirm this interpretation by finding corroborating evidence in other independent observations first. Much more work needs to be done.”

Source : scientificamerican

Saturday 5 October 2013

Scientists develop new theory about how life forms on asteroids

 

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Scientists have a working theory on how life may have come to Earth via an asteroid. But how did life get onto an asteroid in the first place? Several theories exist, but they're all a little bit different. Scientists at Rensselaer Polytechnic Institute, however, have come up with a new theory that could properly explain how organic material forms on an asteroid.

The theories most often taught in astrobiology revolve around the idea that the asteroids were once warm enough that they could sustain liquid water, which is necessary for organic molecules to form. The space where they originated in is cold, so how did they get heated up to the right temperature? One theory states that the asteroids were heated radioactively, similar to Earth’s interior. The other popular theory involves how plasma interacts with a magnetic field. However, both of these theories are based on the assumption that the asteroid belt between Jupiter and Mars was once warm enough to do do this. Unfortunately, these theories don’t work because the sun was much dimmer back then than originally thought, meaning that the area was even colder than it is now.

The Rensselaer scientists started by looking at the theory involving magnetic fields. That theory states that an asteroid creates an electric field when it moves through a magnetic field. This heats up the asteroid. This theory makes the assumption that a strong solar wind was present, but that has been disproved.

However, starting with this theory gave them something to work with. They used a new understanding of how the process works, and re-calculated the electric field. With that, they determined that something called multi-fluid magneto-hydrodynamics was also at work on the asteroids. This regards how plasma interacts when introduced to a magnetic field. Generally speaking, the plasma’s neutral particles rub up against other particles and create friction. This friction creates heat. This heat creates the correct temperature for organic molecules to form.

Although the scientists feel that this theory is a good one, they still believe there are more questions to be asked and answered regarding the origin of life on asteroids.