Tag: astronomy

Mars Is Spectacular This Month – Here’s The Best Way To Spy The Red Planet

If you look at the sky tonight and spot a very bright star, it may well be a planet. Mars is the closest it has been to Earth for 15 years – and therefore the brightest.

Mars shines through reflected light,” says Robert Massey, the deputy executive director of the Royal Astronomical Society.

That means that when it’s closer to the Earth it appears brighter, because its apparent size is bigger.” It won’t be this visible again until 2035.

So, how best to see it? First, make sure tall trees or buildings are not obscuring the view. Ideally, you want a clear horizon. Then, look south.




It will be obvious, because it’s bright, it doesn’t twinkle and it has a distinct reddish tinge,” says Massey, who suggests Somerset, Devon and Dorset as good locations for spotting it.

The best Mars-gazing time is 1am, but it rises earlier in the evening.

You can see Mars with the naked eye, but a pair of binoculars would help,” says Massey. “If you have a small telescope, you may be lucky to see a polar ice cap.

If you are an amateur with good equipment, the details to look out for are two polar ice caps, mountains or volcanoes, and sunken, crater-like features. Massey suggests contacting your local astronomical society about public viewing events.

Hubble’s views of Mars at two recent oppositions

When is the best time to see Mars?

According to NASA, Mars Opposition begins Friday, July 27 around midnight.

Mars will be visible between Friday, July 27 and Monday, July 30, making its closest approach — 35.8 million miles to be exact — on Tuesday, July 31 at around 4 a.m. E.T.

Mars will be at its brightest Friday night due to an opposition surge that is affected by the planet’s angle of the sun — giving you the clearest view of the Red Planet.

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Signs Of Life On Europa May Be Just Beneath The Surface

If signs of life exist on Jupiter’s icy moon Europa, they might not be as hard to find as scientists had thought, a new study reports.

The 1,900-mile-wide (3,100 kilometers) Europa harbors a huge ocean beneath its icy shell.

What’s more, astronomers think this water is in contact with the moon’s rocky core, making a variety of complex and intriguing chemical reactions possible.

Researchers therefore regard Europa as one of the solar system’s best bets to harbor alien life.

Europa is also a geologically active world, so samples of the buried ocean may routinely make it to the surface—via localized upwelling of the ocean itself, for example, and/or through geyser-like outgassing, evidence of which has been spotted multiple times by NASA’s Hubble Space Telescope.

NASA aims to hunt for such samples in the not-too-distant future. The agency is developing a flyby mission called Europa Clipper, which is scheduled to launch in the early 2020s.

Clipper will study Europa up close during dozens of flybys, some of which might be able to zoom through the moon’s suspected water-vapor plumes.

And NASA is also working on a possible post-Clipper lander mission that would search for evidence of life at or near the Europan surface.




 

It’s unclear, however, just how deep a Europa lander would need to dig to have a chance of finding anything.

That’s because Europa orbits within Jupiter’s radiation belts and is bombarded by fast-moving charged particles, which can turn amino acids and other possible biosignatures into mush.

That’s where the new study comes in.

NASA scientist Tom Nordheim and his colleagues modeled Europa’s radiation environment in detail, laying out just how bad things get from place to place.

They then combined these results with data from laboratory experiments documenting how quickly various radiation doses carve up amino acids (a stand-in here for complex biomolecules in general).

The researchers found significant variation, with some Europan locales (equatorial regions) getting about 10 times the radiation pounding of others (middle and high latitudes).

At the most benign spots, the team determined, a lander would likely have to dig just 0.4 inches (1 centimeter) or so into the ice to find recognizable amino acids.

In the high-blast zones, the target depth would be on the order of 4 to 8 inches (10 to 20 cm).

That latter range is still quite manageable, said Nordheim, who’s based at the California Institute of Technology and NASA’s Jet Propulsion Laboratory, both of which are in Pasadena.

That’s good news for the potential lander mission, Nordheim added: With radiation exposure seemingly not a limiting factor, planners can feel free to target the areas of Europa most likely to harbor fresh ocean deposits—the fallout zone beneath a plume, for example—wherever they may lie.

Scientists still haven’t identified any such promising touchdown areas; the Europa imagery captured to date just hasn’t been sharp enough. But Europa Clipper’s work should change things, Nordheim said.

When we get the Clipper reconnaissance, the high-resolution images—it’s just going to be a completely different picture,” he said. “That Clipper reconnaissance is really key.”

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Puzzling Cosmic Glow Is Caused by Diamond Dust Glamming Up Stars

Diamond dust is responsible for a mysterious glow emanating from certain regions of the Milky Way galaxy, a new study reports.

Astronomers have long known that some type of very small, rapidly spinning particle is throwing off this faint light, which is known as anomalous microwave emission (AME). But they couldn’t identify the exact culprit — until now.

In the new study, researchers used the Green Bank Telescope in West Virginia and the Australia Telescope Compact Array to search for AME light in 14 newborn star systems across the Milky Way.

They spotted the emissions in three of these systems, coming from the planet-forming disks of dust and gas swirling around the stars.

This is the first clear detection of anomalous microwave emission coming from protoplanetary disks,” study co-author David Frayer, an astronomer with the Green Bank Observatory, said in a statement.




The study team also detected the unique infrared-light signatures of nanodiamonds — carbon crystals far smaller than a grain of sand — in these same three systems, and nowhere else.

In fact, these [signatures] are so rare, no other young stars have the confirmed infrared imprint,” study lead author Jane Greaves, an astronomer at Cardiff University in Wales, said in the same statement.

The researchers don’t think this is a coincidence.

One to 2 percent of the total carbon in these protoplanetary disks has been incorporated into nanodiamonds, according to the team’s estimates.

Another leading AME-source candidate, a family of organic molecules known as polycyclic aromatic hydrocarbons (PAHs), doesn’t hold up under scrutiny, the researchers said.

The infrared signature of PAHs has been identified in multiple young star systems that lack an AME glow, they noted.

The new results could help astronomers better understand the universe’s early days, study team members said.

Scientists think the universe expanded far faster than the speed of light shortly after the Big Bang, in a brief period of “cosmic inflation.

If this did indeed happen, it should have left a potentially detectable imprint — an odd polarization of the cosmic microwave background, the ancient light left over from the Big Bang.

The new study provides “good news for those who study polarization of the cosmic microwave background, since the signal from spinning nanodiamonds would be weakly polarized at best,” said co-author Brian Mason, an astronomer at the National Radio Astronomy Observatory in Charlottesville, Virgina.

This means that astronomers can now make better models of the foreground microwave light from our galaxy, which must be removed to study the distant afterglow of the Big Bang,” Mason added.

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Saturn Found To Have Noontime Auroras

An international team of researchers has found that Saturn’s fast rotation speed makes it possible for the planet to experience noontime auroras.

In their paper published in the journal Nature Astronomy, the group describes the factors that lead to creation of auroras and how Saturn’s appear to arise.

Auroras on Earth occur when magnetic reconnections (magnetic fields colliding) cause solar flares on the sun. When it happens, plasma carrying a magnetic field is shot out into space, some of which makes its way to Earth.

When it collides with our planet’s magnetic field, auroras occur. The same process has been observed on Venus, Mars, Jupiter, Saturn and Uranus.

In this new effort, the researchers were studying data sent back from the Cassini spacecraft, which orbited Saturn for 13 years.




They were looking specifically at data that would provide more information regarding magnetic reconnections on the planet—prior research had shown that they occur on the dayside of the magnetopause (the point where the planet’s magnetic field meets the solar wind).

There was also evidence that they occur on the nightside of its magnetodisk, which is a plasma ring formed near the equator by water and other materials emitted from its moons.

But prior research had also suggested that there would be no reconnections on the dayside of the planet’s magnetodisk because the solar winds made the to too thick for them to occur.

But the researchers found evidence of reconnections in the magnetodisk at noontime anyway. The researchers suggest this apparent anomaly is likely due to Saturn’s high spin rate (a day is just 10 hours).

The high rate, they note, likely compresses the magnetodisk, making it thin enough for reconnections to occur. The team also suggests that the reconnections they measured appear to be strong enough to create auroras.

The researchers suggest that their findings indicate that unknown auroras might be happening on other planets as well, but have been overlooked because planet spin speed was not factored into calculations.

They further suggest that similar reconnections might also be behind some unexplained pulses seen from Jupiter.

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‘Planet Nine’ Can’t Hide Much Longer, Scientists Say

Planet Nine’s days of lurking unseen in the dark depths of the outer solar system may be numbered.

The hypothetical giant planet, which is thought to be about 10 times more massive than Earth, will be discovered within 16 months or so, astronomer Mike Brown predicted.

I’m pretty sure, I think, that by the end of next winter — not this winter, next winter — I think that there’ll be enough people looking for it that … somebody’s actually going to track this down,” Brown said during a news conference at a joint meeting of the American Astronomical Society’s Division for Planetary Sciences (DPS) and the European Planetary Science Congress (EPSC) in Pasadena, California.

Brown said that eight to 10 groups are currently looking for the planet.

At the “next one of these [DPS-EPSC meetings], we’ll be talking about finding Planet Nine instead of just looking for it,” added Brown, who’s based at the California Institute of Technology (Caltech) in Pasadena.




That would be a pretty quick path from hypothetical planet to confirmed world. The existence of Planet Nine was seriously proposed for the first time just in 2014, by astronomers Scott Sheppard and Chadwick Trujillo, of the Carnegie Institution for Science in Washington, D.C., and the Gemini Observatory in Hawaii, respectively.

Sheppard and Trujillo noted that the dwarf planet Sedna, the newfound object 2012 VP113 and several other bodies far beyond Pluto share certain odd orbital characteristics, a coincidence that would make sense if their paths through space had been shaped by an unseen, giant “perturber” in the region.

The researchers suggested that this putative planet is perhaps two to 15 times more massive than Earth and lies hundreds of astronomical units (AU) from the sun.

This interpretation was bolstered in January of this year by Brown and fellow Caltech astronomer Konstantin Batygin, who found evidence of a perturber’s influence in the orbits of a handful of additional distant objects.

This “Planet Nine,” as Batygin and Brown dubbed the putative world, likely contains about 10 Earth masses and orbits on a highly elliptical path whose aphelion is about 1,000 AU, the researchers said.

The evidence for Planet Nine’s existence has continued to grow over the past nine months, as several different research teams have determined that the orbits of other small, distant objects appear to have been sculpted as well.

This is well within reach of the giant telescopes,” he said.

The Subaru telescope, I think, on Mauna Kea, [in Hawaii] — the Japanese national telescope — is the prime instrument for doing the search. But there are a lot of other people who have clever ideas on how to find it, too, that are trying with their own telescopes.”

So which research team will ultimately find Planet Nine? Brown said he isn’t sure, and he stressed that getting credit for the historic discovery should be a secondary concern for astronomers.

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Scientists Probably Found The Next Big Discovery In Astronomy Years Ago – But They Don’t Know It Yet

This year, astronomers stumbled across a fascinating finding: Thousands of black holes likely exist near the center of our galaxy.

The X-ray images that enabled this discovery weren’t from some state-of-the-art new telescope. Nor were they even recently taken – some of the data was collected nearly 20 years ago.

No, the researchers discovered the black holes by digging through old, long-archived data.

Discoveries like this will only become more common, as the era of “big data” changes how science is done.




The evolution of astronomy

Sixty years ago, the typical astronomer worked largely alone or in a small team. They likely had access to a respectably large ground-based optical telescope at their home institution.

Their observations were largely confined to optical wavelengths – more or less what the eye can see.

That meant they missed signals from a host of astrophysical sources, which can emit non-visible radiation from very low-frequency radio all the way up to high-energy gamma rays.

For the most part, if you wanted to do astronomy, you had to be an academic or eccentric rich person with access to a good telescope.

Astronomers are gathering an exponentially greater amount of data every day – so much that it will take years to uncover all the hidden signals buried in the archives.

Old data was stored in the form of photographic plates or published catalogs. But accessing archives from other observatories could be difficult – and it was virtually impossible for amateur astronomers.

Unlocking new science

The data deluge will make astronomy become a more collaborative and open science than ever before. Thanks to internet archives, robust learning communities and new outreach initiatives, citizens can now participate in science.

For example, with the computer program [email protected], anyone can use their computer’s idle time to help search for gravitational waves from colliding black holes.

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From Pancakes To Soccer Balls, New Study Shows How Galaxies Change Shape As They Age

A selection of SAMI galaxies imaged with the Hyper Suprime Cam on the Subaru Telescope in Hawaii. National Astronomical Observatory of Japan (NAOJ), Caroline Foster (The University of Sydney) and Dan Taranu (University of Western Australia)

Galaxies are a fundamental part of the 13.7 billion-year-old universe. Understanding how a system as complex and striking as our own Milky Way galaxy formed after the Big Bang is one of the great themes of modern astronomy.

Our research, published today in Nature Astronomy, has identified a surprising connection between the age of a galaxy and its three-dimensional shape.

As galaxies get older they get rounder, and fall victim to the middle-aged spread that catches many of us humans here on Earth.

We’ve known for a long time that shape and age are linked in very extreme galaxies – that is, very flat ones and very round ones.

But this is the first time we have shown this is true for all kinds of galaxies – all shapes, all ages, all masses.




Unveiling the true face of a galaxy

In this study we calculated both the age and shape of galaxies using different techniques.

Assigning an age to a galaxy is tricky. They don’t have a single birth date for when they suddenly popped into existence.

We assessed the average age of the stars in a galaxy as a measure of the galaxy’s age. Young galaxies have a large fraction of recently formed hot blue stars, whereas old galaxies mostly contain colder red stars formed shortly after the Big Bang.

Spectroscopy — splitting the light from a galaxy into many different colours — allows us to measure the average age of stars in a galaxy.

This technique gives a much higher precision than simply using blue or red images as is typically done.

To measure a galaxy’s true three-dimensional shape and ellipticity, you have to measure how its stars move around.

Ellipticity is simply a measure of how squashed a galaxy is with respect to a perfect sphere. An ellipticity of zero means a galaxy is a perfect sphere like a soccer ball.

But as the measured ellipticity increases from zero towards one, the galaxy becomes more and more squashed – from a roundish pumpkin shape to a thin disk like a pancake.

We see galaxies as two-dimensional images projected onto the sky, but that doesn’t tell us what they really look like in three dimensions.

If we can also measure how the stars in a galaxy are moving we can infer their true, three-dimensional shape.

Spectroscopy lets us do this via the Doppler effect. We can measure shifts in the wavelength of light emitted by stars, which depend on whether those stars are moving towards us or away from us, and so measure their motions.

We did this using SAMI, the Sydney-Australian-Astronomical-Observatory Multi-object Integral-Field Spectrograph, on the 3.9-metre Anglo-Australian Telescope at Siding Spring Observatory.

The SAMI instrument provides 13 optical fibre units that can “dissect” galaxies using spectroscopy, providing unique 3D data.

Over the past couple of years, the SAMI Galaxy Survey team has gathered 3D measurements for more than a thousand galaxies of all kinds, and with a hundred-fold range in mass.

Closer to home

If we look at our own Milky Way galaxy, which is more than 10 billion years old, we can see examples of this story.

The youngest part of the Milky Way, where stars are still being formed, is the thin disk, which has a very squashed, pancake-like shape.

The Milky Way also contains rounder and older components, a thick disk and a bulge, but their origin is still mostly unknown.

We know that eventually the Milky Way will merge with our galactic neighbour, the Andromeda galaxy. Predictions are that this will result in a very round, very old giant elliptical galaxy.

So, by studying the processes that shape other nearby galaxies, we can learn a lot about the past, and the fate of our own.

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The March 31 Blue Moon Is The 2nd Blue Moon Of 2018

We had a Blue Moon on January 31, 2018. It was a supermoon, too, and underwent a total eclipse.

And another full moon that carries the name Blue Moon this weekend, last Saturday night, March 31. Both the January and March 2018 Blue Moons are blue in name only.

Both are the second of two full moons to fall within a single calendar month. Two Blue Moons in a year is indeed rare.

We haven’t had a year with two Blue Moons since 1999 and won’t have one again until January and March, 2037.




In recent years, people have been using the name Blue Moon for two different sorts of moons. The first can be the second of two full moons in a single calendar month, as with the January 31 and March 31 Blue Moons.

An older definition says a Blue Moon is the third of four full moons in a single season.

Meanwhile, the month of February 2018 had no full moon at all.

Someday, you might see an actual blue-colored moon. Meanwhile, the moon you saw last Saturday night does not look blue at all.

Blue-colored moons in photos are made using special blue camera filters or in a post-processing program such as PhotoShop.

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Unprecedented Image Of A Supernova 80 Million Light Years Away Is Captured For The First Time By An Amateur Astronomer

The first burst of light given off by an exploding star has been captured for the first time by an amateur astronomer in Argentina.

Observations of a dying star 80 million light-years away, taken by Víctor Buso, 60, has given scientists their first view of the initial flash given off by a supernova.

To date, no one has been able to capture the ‘first optical light’ from a supernova, since stars explode seemingly at random in the sky, and the burst is fleeting.

Most are only spotted a long time after the initial blast, making Mr Buso’s one-in-ten-million observations ‘unprecedented‘, scientists said.

The new data provide important clues to the physical structure of the star just before its catastrophic demise and to the nature of the explosion itself.

Professional astronomers have long been searching for such an event,” said University of California at Berkeley astronomer Dr Alex Filippenko, who followed up the lucky discovery with scientific observations of the explosion, called SN 2016gkg.




Observations of stars in the first moments they begin exploding provide information that cannot be directly obtained in any other way.”

It’s like winning the cosmic lottery.”

During tests of a new camera, Mr. Buso snapped images through his 16-inch telescope of the galaxy NGC 613, which is 80 million light-years from Earth.

He took a series of short-exposure photographs of the spiral galaxy, accidentally capturing it before and after the supernova’s ‘shock breakout’.

This is when a pressure wave from the star’s exploding core hits and heats gas at the star’s surface to a very high temperature, causing it to flash and rapidly brighten.

Upon examining the images, Mr. Buso, of Rosario, Argentina, noticed a faint point of light quickly brightening near the end of a spiral arm that was visible in his second set of images but not his first.

Astronomer Dr Melina Bersten and her colleagues at the Instituto de Astrofísica de La Plata in Argentina soon learned of the serendipitous discovery.

They realized that Mr. Buso had caught a rare event; part of the first hour after light emerges from a massive exploding star.

She estimated Mr Buso’s chances of such a discovery, his first supernova, at one in 10 million or perhaps even as low as one in 100 million.

Dr Bersten contacted an international group of astronomers to help conduct additional frequent observations of SN 2016gkg.

A series of subsequent studies have revealed more about the type of star that exploded and the nature of the explosion.

Mr. Buso’s discovery, snapped in September 2016, and results of follow-up observations have now been published in the journal Nature.

Buso’s data are exceptional,” Dr. Filippenko added.

This is an outstanding example of a partnership between amateur and professional astronomers.

The astronomer and his colleagues obtained a series of seven spectra, where the light is broken up into its component colors, as in a rainbow.

They used the Shane 3-meter telescope at the University of California’s Lick Observatory near San Jose, California, and the twin 10-meter telescopes of the W. M. Keck Observatory on Maunakea, Hawaii.

This allowed the international team to determine that the explosion was a Type IIb supernova: The explosion of a massive star that had previously lost most of its hydrogen envelope.

Combining the data with theoretical models, the team estimated that the initial mass of the star was about 20 times the mass of our Sun.

They suggest it lost most of its mass to a companion star and slimmed down to about five solar masses prior to exploding.

Further analyses of the signal could provide further information on the star’s structure and uncover more secrets about supernovas.

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A New Study Suggests That As A Star Begins To Die And Slowly Expands Outward, It Would Temporarily Light Up As It Eats The Worlds It Hosts

600 light years away, in the constellation of Auriga, there is a star in some ways similar to our Sun. It’s a shade hotter (by about 800° C), more massive, and older.

Oddly, it appears to be laced with heavy elements: more oxygen, aluminum, and so on, than might be expected. A puzzle.

Then, last year, it was discovered that this star had a planet orbiting it. A project called WASP – Wide Area Search for Planets, a UK telescope system that searches for exoplanets — noticed that the star underwent periodic dips in its light.

This indicates that a planet circles the star, and when the planet gets between the star and us, it blocks a tiny fraction of the starlight.




The planet is a weirdo, for many reasons… but it won’t be weird for too much longer. That’s because the star is eating it.

OK, first, the planet. Called WASP 12b, it was instantly pegged as an oddball. The orbit is only 1.1 days long! Compare that to our own 365 day orbit, or even Mercury’s 88 days to circle the Sun.

This incredibly short orbital period means this planet is practically touching the surface of its star as it sweeps around at over 220 km/sec!

That also means it must be very hot; models indicate that the temperature at its cloud tops would be in excess of 2200°C.

Not only that, but other numbers were odd, too. WASP 12b was found to be a bit more massive and bigger than Jupiter; about 1.8 times its size and 1.4 times its mass.

That’s too big! Models indicate that planets this massive have a funny state of matter in them; they are so compressible that if you add mass, the planet doesn’t really get bigger, it just gets denser.

In other words, you could double Jupiter’s mass and its size wouldn’t increase appreciably, but since the mass goes up, so would its density.

But WASP 12b isn’t like that. In fact, it has a lower density than Jupiter, and is a lot bigger! Something must be going on… and when you see a lot of weird things all sitting in one place, it makes sense to assume they’re connected.

In this case it’s true: that planet is freaking hot, and that’s at the heart of this mess. Heating a planet that much would not exactly be conducive to its well-being.

When you heat a gas it expands, which would explain WASP 12b’s big size. It’s puffy! But being all bloated that close to a star turns out to be bad for your health.

Astronomers used Hubble to observe the planet in the ultraviolet and found clear signs of all sorts of heavy elements, including sodium, tin, aluminum, magnesium, and manganese, as well as, weirdly, ytterbium*.

Moreover, they could tell from the data that these elements existed in a cloud surrounding the planet, like an extended atmosphere going outward for hundreds of thousands of kilometers.

This explains the peculiar high abundance of heavy metals in the star I mentioned at the beginning of this post; they come from the planet! But not for long.

Given the mass of the planet and the density of the stream, it looks like it has roughly ten million years left. At that point, supper’s over: there won’t be anything left for the star to eat.

In reality it’s hard to say exactly what will happen; there may be a rocky/metal core to the planet that will survive. But even that is so close to the star that it will be a molten blob of goo.

The way orbits work, the way the dance of gravity plays out over time, the planet itself may actually be drawn inexorably closer to its star. Remember, too, the star is old, and will soon start to expand into a red giant.

So the planet is falling and the star is rising; eventually the two will meet and the planet will meet a fiery death.

All in all, it sucks to be WASP 12b.

But it’s cool to be an astronomer!

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