Tag: space

Scientist Have Discovered A Massive Crater Hides Beneath Greenland’s Ice

There’s something big lurking beneath Greenland’s ice. Using airborne ice-penetrating radar, scientists have discovered a 31-kilometer-wide crater — larger than the city of Paris — buried under as much as 930 meters of ice in northwest Greenland.

The meteorite that slammed into Earth and formed the pit would have been about 1.5 kilometers across, researchers say.

That’s large enough to have caused significant environmental damage across the Northern Hemisphere, a team led by glaciologist Kurt Kjær of the University of Copenhagen reports November 14 in Science Advances.

Although the crater has not been dated, data from glacial debris as well as ice-flow simulations suggest that the impact may have happened during the Pleistocene Epoch, between 2.6 million and 11,700 years ago.

The discovery could breathe new life into a controversial hypothesis that suggests that an impact about 13,000 years ago triggered a mysterious 1,000-year cold snap known as the Younger Dryas.




Members of the research team first spotted a curiously rounded shape at the edge of Hiawatha Glacier in northwest Greenland in 2015, during a scan of the region by NASA’s Operation IceBridge.

The mission uses airborne radar to map the thickness of ice at Earth’s poles. The researchers immediately suspected that the rounded shape represented the edge of a crater, Kjær says.

For a more detailed look, the team hired an aircraft from Germany’s Alfred Wegener Institute that was equipped with ultra-wideband radar, which can send pulses of energy toward the ice at a large number of frequencies.

Using data collected from 1997 to 2014 from Operation Icebridge and NASA’s Program for Arctic Regional Climate Assessment, as well as 1,600 kilometers’ worth of data collected in 2016 using the ultra-wideband radar, the team mapped out the inner and outer contours of their target.

The object is almost certainly an impact crater, the researchers say. “It became clear that our idea had been right from the beginning,” Kjær says.

What’s more, it is not only the first crater found in Greenland but also one of the 25 or so largest craters yet spotted on Earth. And it has held its shape beautifully, from its elevated rim to its bowl-shaped depression.

Those data clearly suggest that the impact is at least 11,700 years old, Kjær says.

And the rim of the crater appears to cut through a preexisting ancient river channel that must have flowed across the land before Greenland became covered with ice about 2.6 million years ago.

That time span — essentially, the entire Pleistocene Epoch — is a large range.

The team is working on further narrowing the possible date range, with more sediment samples, simulations of the rate of ice flow and possibly cores collected from within the crater.

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A Frozen Super-Earth Is Close But You Won’t Want To Visit It

Night by night, star by star, astronomers are edging ever closer to learning just how crowded our universe really is—or at least our galaxy, anyway.

A quarter century after the first exoplanets were found orbiting other stars, statistics from the thousands now known have revealed that, on average, each and every stellar denizen of the Milky Way must be accompanied by at least one world.

Look long and hard enough for a planet around any given star in our galaxy and you are practically guaranteed to find something sooner or later.

But even a crowded universe can be a lonely place. Our planet-rich Milky Way may prove to be life-poor. Of all the galaxy’s known worlds, only a figurative handful resemble Earth in size and orbit.

Each occupying a nebulous “Goldilocks” region of just-rightness—a fairy-tale-simple ideal in which a world is neither too big nor too small, neither too hot nor too cold, to sustain liquid water and life on its surface.

Instead, most of the Milky Way’s planets are worlds theorists failed to predict and have yet to fit comfortably in any conception of habitability: “super-Earths” bigger than our familiar planet but smaller than Neptune.

No super-Earths twirl around our sun for solar system–bound scientists to directly study, making it that much harder to know whether any elsewhere are Goldilocks worlds—or, for that matter, whether any one-size-fits-all metric of habitability is hopelessly naive.




A Frozen Super-Earth?

If you live in a city of millions of people, you are not interested in meeting every one of them—but maybe you want to meet your immediate neighbors,” says lead author Ignasi Ribas, an astronomer at the Institute of Space Studies of Catalonia in Spain.

“This is what we are doing for the planetary systems of the stars that surround us. Otherwise we cannot answer the big questions. How does our solar system and our Earth fit in with the rest of the galaxy?

“Are there other habitable or inhabited planets? Barnard’s Star b is not giving us those answers just yet, but it is telling us part of the story we need to know.”

Located in the constellation of Ophiuchus, Barnard’s Star is so dim in visible light that it cannot be seen with unaided eyes.

Yet it has been a favorite of astronomers since 1916, when measurements revealed its apparent motion across the sky was greater than that of any other star relative to our sun.

A sign of its extremely close cosmic proximity. The star’s nearness to us is only temporary—within tens of thousands of years, its trajectory will have swept it out of our solar system’s list of top five closest stars.

According to Ribas and his colleagues, the candidate planet is at least three times heavier than our own, and circles its star in a 233-day orbit.

That would put it in the torrid orbital vicinity of Venus around our yellow sun, but Barnard’s Star is a comparatively pint-size and dim red dwarf star.

This means its newfound companion is near the “snow line,” the boundary beyond which water almost exclusively exists as frozen ice—a region around other stars thought to be chock-full of planets, but that astronomers have only just begun to probe for small worlds.

Alternatively, the planet might be covered by a thick, insulating blanket of hydrogen leftover from its birth in a spinning disk of gas and dust around its star.

Although hydrogen on smaller, hotter worlds would dissipate into space, super-Earths in frigid orbits might manage to hang on to enough of the gas to build up a massive planet-warming greenhouse effect—a possibility that throws Earth-centric Goldilocks ideas into tumult.

If this mechanism operates on Barnard’s Star b or other cold super-Earths, “our dreams that every star may have a habitable planet could well come true,” says Sara Seager, a planet-hunting astrophysicist at Massachusetts Institute of Technology who was not involved with Ribas’s study.

“There are some crazy worlds out there.”

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How the Sun Set Off Dozens of Mines During the 1972 Vietnam War

A sea mine explodes off the coast of North Vietnam during Operation End Sweep.

In 1972, the United States was deep into the Vietnam War with little end in sight. North Vietnam had just launched an offensive on the South, the Easter Offensive.

The United States military was desperate to gain any advantage it could, so top brass hatched a plan to cover the port of Haiphong with underwater mines.

Starting in May of that year, Operation Pocket Money saw thousands of mines dropped in the water outside Haiphong’s port.

Those mines were supposed to sit there for about a year, but on August 4, dozens of them exploded prematurely. But they weren’t set off by passing ships; instead, it seems that the mines were triggered by the sun.

At the time, the military suspected solar interference might be involved in the explosion, but the research was classified until now.

Since the declassification, a group of civilian researchers revisited the incident and confirmed the military’s suspicions: Solar effects were to blame.

The key lies in how the mines are triggered to explode. Each mine has a magnetic sensor that can detect subtle changes in magnetic fields.

If a passing ship drifts too close to the mines with its metal hull, the altered magnetic field would set off the detonator.




Unfortunately, there are plenty of ways to alter a magnetic field aside from the hulls of ships. One significant source of magnetic fields is the sun, which produces the strongest magnetic field in the solar system.

Occasionally, large eruptions from the surface of the sun—called solar flares—can send huge plumes of magnetic material hurtling toward Earth.

When those solar flares reach Earth, they can cause all kinds of magnetic disturbances. At their most mild, they’re responsible for the Northern Lights and other auroras.

At their worst, they can mess with GPS systems, interfere with communications, and in one particularly notable case, almost start a nuclear war.

In this case, an unusually strong solar flare was enough to mess up the delicate sensors on some of the Navy’s mines placed in Haiphong’s harbor.

According to the research paper, that 1972 solar flare was one of the strongest on record, and in addition to exploding a few dozen mines also interfered with telephone lines and triggered power outages around the world.

This event underscores just how disruptive and dangerous solar flares can be. A high-intensity solar flare like the 1972 event could cripple our satellite networks if it hit us today, and so far we’ve been lucky to avoid something like that.

But we can’t be lucky forever, and if a repeat of the 1972 flare hits us now, exploding mines are going to be the least of our worries.

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Our bodies Are Made Of Remnants Of Stars And Massive Explosions In The Galaxies

galaxy

It seems natural to assume that the matter from which the Milky Way is made was formed within the galaxy itself, but a series of new supercomputer simulations suggests that up to half of this material could actually be derived from any number of other distant galaxies.

This phenomenon, described in a paper by group of astrophysicists from Northwestern University in the US who refer to it as “intergalactic transfer”, is expected to open up a new line of research into the scientific understanding of galaxy formation.




Led by Daniel Anglés-Alcázar, the astrophysicists reached this intriguing conclusion by implementing sophisticated numerical simulations which produced realistic 3D models of galaxies and followed their formation from shortly after the Big Bang to the present day.

The researchers then employed state-of-the-art algorithms to mine this sea of data for information related to the matter acquisition patterns of galaxies.

Through their analysis of the simulated flows of matter, Anglés-Alcázar and his colleagues found that supernova explosions eject large amounts of gas from galaxies, which causes atoms to be conveyed from one system to the next via galactic winds.

galaxy

In addition, the researchers note that this flow of material tends to move from smaller systems to larger ones and can contribute to up to 50 percent of the matter in some galaxies.

Anglés-Alcázar and his colleagues use this evidence, which is published in Monthly Notices of the Royal Astronomical Society, to suggest that the origin of matter in our own galaxy including the matter that makes up the Sun, the Earth, and even the people who live on it may be far less local than traditionally believed.

galaxy

“It is likely that much of the Milky Way’s matter was in other galaxies before it was kicked out by a powerful wind, traveled across intergalactic space and eventually found its new home in the Milky Way,” Anglés-Alcázar says.

The team of astrophysicists now hopes to test the predictions made by their simulations using real-world evidence collected by the Hubble Space Telescope and other ground-based observatories.

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Mysterious Interstellar Object Floating In Space Might Be Alien, Say Harvard Researchers

A graphic showing `Oumuamua’s path through the Solar System.

The head of Harvard’s department of astronomy thinks that there’s a possibility that a strange object that visited our Solar System from interstellar space may be an alien probe sent from a distant civilization.

He and a colleague outlined their idea in a paper published this week analyzing what the mysterious space object might be, setting off a media frenzy.

But let’s take a breath before we jubilantly cry “aliens.” A single idea about what this object could be doesn’t make it the only explanation, and many scientists still argue that a natural explanation is more plausible.

To add a bit of context, one of the scientists making this “exotic” claim is currently working on an initiative to look for extraterrestrial life in deep space, by sending probes from Earth to other star systems.

The paper that captured everyone’s attention is written by Harvard astrophysicists Avi Loeb and Shmuel Bialy, who tried to describe some weird behavior exhibited by a space rock called `Oumuamua.

Spotted last October, `Oumuamua is a mysterious object that is passing through our Solar System, coming from some unknown deep-space origin.

Objects like this one are thought to pass through our Solar System all the time, but this is the first exo-comet — or a comet from outside our cosmic neighborhood — that we’ve ever detected.

In addition to being a rare find, `Oumuamua is a bit bizarre. Astronomers expected a visitor of this kind to be an icy comet, surrounded by a trail of gas and dust as it passed close to the Sun.




But `Oumuamua seems to lack this kind of cloud, making it look more like an asteroid, which is mostly made of rock and metal. So no one was quite sure what this thing was — a comet, an asteroid, or something totally new.

Then after analyzing `Oumuamua’s orbit, scientists from the European Space Agency noticed that the object was accelerating, more so than it should be if it was just interacting with the gravity of the planets and Sun in our Solar System.

They concluded that `Oumuamua must be a comet; the Sun is likely heating up ice within the object, creating gas that provides an extra boost of speed.

However, Loeb and Bialy are skeptical about this “outgassing” claim, mostly because no one was able to observe gas and dust coming from `Oumuamua.

They also point to recent research from another lab, which is still under review by other scientists, that indicates that if gas were coming from this object, it would change how the rock is rotating — something that hasn’t been observed.

This rules out the possibility that it’s a comet,” Loeb said.

The comet ISON and its tail of gas and dust, as seen by the Hubble Space Telescope

Of course, the possibility exists. But aliens are a very bold claim to make when natural explanations are still on the table.

I can understand the excitement, and as a scientist, I can’t sit here and say I have 100 percent evidence this was a natural object,” Fitzsimmons says. “It’s just that all the observations can be matched with a natural object.”

And that could be a problem when we actually do find signs of alien life one day.

Astronomers are finding new planets outside our Solar System all the time, and we’re working on more sophisticated technology to peer into the atmospheres of these worlds.

One day, we may find solid evidence that life exists in deep space, but it may be hard for the public to swallow if they think aliens have already been discovered.

I don’t want people to think we already saw that when it actually happens,” says Mack. “I want people not to be super cynical about claims about aliens by the time we actually have something that is really solid evidence.”

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Two Big NASA Space Missions Ended This Week, But Don’t Panic

It’s easy for a superstitious mind to jump to anxious conclusions from this week, after NASA announced the end of two long-running missions: the exoplanet-hunting Kepler space telescope and the Dawn mission that visited the asteroid belt.

And those high-profile finales come in the midst of a spree of other spacecraft troubles: the Opportunity rover on Mars remains silent nearly five months after a planet-engulfing dust storm, and the Hubble Space Telescope and Chandra X-Ray Observatory were both briefly offline in October.

But as NASA personnel stressed during a news conference Tuesday (Oct. 30) to announce the end of the Kepler mission, the sudden spurt of bad news is no reason to panic.

We always try to get as much science as we can out of our spacecraft,” Paul Hertz, NASA’s head of astrophysics in the Science Mission Directorate, said during the news conference, adding that the agency has more than 60 science spacecraft at work right now.

If you only pick out the ones that are getting toward the end of their life then you can make a story, but if you look at the entire portfolio of spacecraft, I don’t think we have a problem at all, I think we are in a golden age of NASA science,” Hertz said.

Both the Kepler telescope, which identified more than 2,600 alien planets, and the Dawn spacecraft, which visited the asteroid Vesta and the dwarf planet Ceres, ended because they no longer had enough gas in the tank.




Engineers on both missions knew their ends were looming, since they could calculate remaining fuel estimates.

Both spacecraft used chemical fuel to twist themselves back toward Earth and beam their findings home; without that fuel there was no way to learn from our distant emissaries.

Sure, each mission could theoretically have been stocked with more fuel, but not without fattening their price tags.

And both missions lasted far longer than they were initially designed to endure, overcoming serious mechanical problems along the way.

When the Kepler mission began in April 2009, it was originally designed to last three years — instead, it lasted until 2013, when two broken reaction wheels forced its original mission to end.

The telescope’s engineers still didn’t abandon it; instead, they reprogrammed it, so that rather than look for exoplanets in one particular patch of the sky, it hopped from region to region.

Reincarnated, the telescope completed another four years of observations.

Dawn also survived reaction-wheel failures that threatened to sideline the spacecraft at the end of its stay at the asteroid Vesta.

In Dawn’s case, engineers rescued it by using fuel to make small adjustments to its position.

This spacecraft also blew past its original timeline, spending 14 months at Vesta instead of the scheduled seven and more than three years at the dwarf planet Ceres instead of the scheduled five months.

Although the fate of the Opportunity rover remains unknown as NASA continues to try to revive it through January, the rover has outpaced its goals just as dramatically as its spacefaring cohorts.

Its mission was originally scheduled to last just 90 Martian days, each about 40 minutes longer than a terrestrial one. Instead, the rover has puttered the Red Planet for more than 14 years.

Beyond the casualty list, NASA also has some beginnings worth remembering. Its Transiting Exoplanet Survey Satellite, or TESS, picked up where Kepler left off, beginning observations in late July, and has already identified multiple possible planets.

The Parker Solar Probe mission to “touch the sun” launched in August and is making its first close approach to our star this week.

NASA’s new Mars lander, called InSight, will touch down just after Thanksgiving, ready to study the Red Planet’s interior, and the New Horizons spacecraft will ring in the new year by swinging past a distant Kuiper Belt object.

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NASA’s Revolutionary Planet-Hunting Telescope Kepler Runs Out of Fuel

NASA’s prolific Kepler Space Telescope has run out of fuel, agency officials announced on Oct. 30, 2018. The planet-hunting space telescope discovered thousands of alien worlds around distant stars since its launch in 2009.

The most prolific planet-hunting machine in history has signed off.

NASA’s Kepler space telescope, which has discovered 70 percent of the 3,800 confirmed alien worlds to date, has run out of fuel, agency officials announced last October 30.

Kepler can no longer reorient itself to study cosmic objects or beam its data home to Earth, so the legendary instrument’s in-space work is done after nearly a decade.

And that work has been transformative.

“Kepler has taught us that planets are ubiquitous and incredibly diverse,” Kepler project scientist Jessie Dotson, who’s based at NASA’s Ames Research Center in Moffett Field, California said.




“It’s changed how we look at the night sky.”

The announcement was not unexpected. Kepler has been running low on fuel for months, and mission managers put the spacecraft to sleep several times recently to extend its operational life as much as possible.

But the end couldn’t be forestalled forever; Kepler’s tank finally went dry two weeks ago, mission team members said during a telecon with reporters today.

This marks the end of spacecraft operations for Kepler, and the end of the collection of science data,” Paul Hertz, head of NASA’s Astrophysics Division, said during the telecon.

Prepping the Kepler spacecraft pre-launch in 2009.

Even though Kepler has closed its eyes, discoveries from the mission should keep rolling in for years to come.

About 2,900 “candidate” exoplanets detected by the spacecraft still need to be vetted, and most of those should end up being the real deal, Kepler team members have said.

A lot of other data still needs to be analyzed as well, Dotson stressed.

And Kepler will continue to live on in the exoplanet revolution it helped spark.

For example, in April, NASA launched a new spacecraft called the Transiting Exoplanet Survey Satellite (TESS), which is hunting for alien worlds circling stars that lie relatively close to the sun (using the transit method, just like Kepler).

Kepler’s death “is not the end of an era,” Kepler system engineer Charlie Sobeck, also of NASA Ames said. “It’s an occasion to mark, but it’s not an end.”

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A NASA Spacecraft Just Broke the Record for Closest Approach to Sun

A NASA sun-studying spacecraft just entered the record books.

In April of 1976, the German-American Helios 2 probe made spaceflight’s closest-ever solar approach, cruising within 26.55 million miles (42.73 million kilometers) of the sun.

But NASA’s Parker Solar Probe zoomed inside that distance today (Oct. 29), crossing the threshold at about 1:04 p.m. EDT (1704 GMT), agency officials said.

Helios 2 also set the mark back then for fastest speed relative to the sun, at 153,454 mph (246,960 km/h).

The Parker Solar Probe is expected to best that today as well, reaching higher speeds at about 10:54 p.m. EDT (0254 GMT on Oct. 30), NASA officials said.

These records will fall again and again over the course of the Parker Solar Probe’s $1.5 billion mission, which began Aug. 12 with a liftoff from Florida’s Cape Canaveral Air Force Station.




The spacecraft will study the sun during 24 close flybys over the next seven years, getting closer and closer to our star with each encounter.

The Parker Solar Probe’s final flyby, in 2025, will bring the craft within a mere 3.83 million miles (6.16 million km) of the sun’s surface.

And the sun’s powerful gravity will eventually accelerate the probe to a top speed of around 430,000 mph (690,000 km/h), NASA officials have said.

The first of these two dozen close encounters is just around the corner: It officially begins Wednesday (Oct. 31), with perihelion (closest solar approach) coming on the night of Nov. 5.

It’s been just 78 days since Parker Solar Probe launched, and we’ve now come closer to our star than any other spacecraft in history,” mission project manager Andy Driesman, from the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, said in a statement.

It’s a proud moment for the team, though we remain focused on our first solar encounter, which begins on Oct. 31.

The spacecraft sports a special carbon-composite shield to protect itself and its instruments from intense heat and radiation during its close flybys.

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NASA’s Eagleworks Lab: Pushing The Boundaries Of Physics

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If we’re ever going to reach other star systems, we need a new type of revolutionary propulsion system. NASA’s Eagleworks Lab is exploring the fringes of physics to find exactly that.

Why Is Pluto No Longer A Planet?

In 2006, Pluto was voted out of the planetary club by members of the International Astronomical Union

But in 2006, it was relegated to the status of dwarf planet by the International Astronomical Union (IAU). So why was Pluto demoted?

Where did the controversy start?

Pluto was discovered in 1930 by US astronomer Clyde Tombaugh, who was using the Lowell Observatory in Arizona.

Textbooks were swiftly updated to list this ninth member in the club. But over subsequent decades, astronomers began to wonder whether Pluto might simply be the first of a population of small, icy bodies beyond the orbit of Neptune.

This region would become known as the Kuiper Belt, but it took until 1992 for the first “resident” to be discovered.

The candidate Kuiper Belt Object (KBO) 1992 QBI was detected by David Jewitt and colleagues using the University of Hawaii’s 2.24m telescope at Mauna Kea.




How did this change things?

Confirmation of the first KBO invigorated the existing debate. And in 2000, the Hayden Planetarium in New York became a focus for controversy when it unveiled an exhibit featuring only eight planets.

The planetarium’s director Neil deGrasse Tyson would later become a vocal figure in public discussions of Pluto’s status.

But it was discoveries of Kuiper Belt Objects with masses roughly comparable to Pluto, such as Quaoar (announced in 2002), Sedna (2003) and Eris (2005), that pushed the issue to a tipping point.

Eris, in particular, appeared to be larger than Pluto – giving rise to its informal designation as the Solar System’s “tenth planet“.

The discovery of other icy objects similar in size to Pluto forced a re-think by the IAU

Prof Mike Brown of the California Institute of Technology (Caltech), who led the team that found Eris, would later style himself as the “man who killed Pluto”, while deGrasse Tyson would later jokingly quip that he had “driven the getaway car”.

The finds spurred the International Astronomical Union to set up a committee tasked with defining just what constituted a planet, with the aim of putting a final draft proposal before members at the IAU’s 2006 General Assembly in Prague.

Under a radical early plan, the number of planets would have increased from nine to 12, seeing Pluto and its moon Charon recognised as a twin planet, and Ceres and Eris granted entry to the exclusive club. But the idea met with opposition.

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