Tag: astronomy

Asteroid From Another Star System Is Unlike Anything Seen Before

The object, called ‘Oumuamua, is probably an asteroid that’s at least 10 times longer than it is wide.

Something strange sailed past Earth last month, and thanks to some quick work, astronomers managed to get their first good look at a visitor from interstellar space.

Now named ‘Oumuamua, Hawaiian for “a messenger from afar arriving first,” the object is the first known lump of rock and ice from another star system, which gives astronomers a chance to glimpse a scrap left over from an alien planet’s formation.

This has been crazy-cool. For the asteroid community, this is as big as the gravitational-wave announcement,” NASA astronomer Joseph Masiero said when the object was discovered, referencing the recent detections of ripples in space-time that have been amazing astrophysicists.

It’s extraordinarily elongated, which is extremely unusual—we don’t see anything like that in our solar system,” says study leader Karen Meech of the University of Hawaii’s Institute for Astronomy.

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Twins! Distant Galaxy Looks Like Our Own Milky Way

Almost like a postcard from across the universe, astronomers have photographed a spiral galaxy that could be a twin of our own Milky Way.

The distant galaxy, called NGC 6744, was imaged by the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the European Southern Observatory’s La Silla Observatory in Chile.

The pinwheel lies 30 million light-years away in the southern constellation of Pavo (The Peacock).

We are lucky to have a bird’s-eye view of the spiral galaxybecause of its orientation, face-on, as seen from Earth. It’s a dead ringer for our own home in the cosmos, scientists say.

If we had the technology to escape the Milky Way and could look down on it from intergalactic space, this view is close to the one we would see — striking spiral arms wrapping around a dense, elongated nucleus and a dusty disc,” according to an ESO statement.

There is even a distorted companion galaxy — NGC 6744A, seen here as a smudge to the lower right of NGC 6744, which is reminiscent of one of the Milky Way’s neighboring Magellanic Clouds.

The main difference between NGC 6744 and the Milky Way is the two galaxies’ size. While our galaxy is roughly 100,000 light-years across, our “twin” galaxy extends to almost twice that diameter, researchers said.

The photogenic object is one of the largest and nearest spiral galaxies to Earth.

It’s about as bright as 60 billion suns, and its light spreads across a large area in the sky about two-thirds the width of the full moon making the galaxy visible as a hazy glow through a small telescope.

The reddish spots along the spiral arms in NGC 6744 represent regions where new stars are being born.

The picture was created by combining four exposures taken through different filters that collected blue, yellow-green and red light and the glow coming from hydrogen gas.

These are shown in the new picture as blue, green, orange and red, respectively.

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Neutron Star Smash-Up Produces Gravitational Waves And Light In Unprecedented Stellar Show​

The 2015 detection of gravitational waves – ripples in the very fabric of space and time – was one of the biggest scientific breakthroughs in a century.

But because it was caused by two black holes merging, the event was all but invisible, detectable indirectly via the LIGO facility.

Now a team of scientists has announced the fifth detection of gravitational waves, but there’s a groundbreaking difference this time around.

The ripples were caused by the collision of two neutron stars, meaning the event was accompanied by light, radio, and other electromagnetic signals for the first time.

First predicted by Albert Einstein over 100 years ago, gravitational waves are caused by cosmic cataclysms like the collision of two black holes, but because of the immense distance.

By the time they reach us here on Earth the distortions are occurring on the subatomic scale.

To observe waves that tiny, LIGO beams lasers down a 4-km (2.5-mi) long tunnel and measures how gravitational waves might warp the beam as they wash over our local corner of spacetime.

That delicate process is effective at confirming the phenomenon, but still somewhat indirect.

This is the first time that the collision of two neutron stars has been detected, and this is the closest and most precisely located gravitational wave signal we’ve received,” says Susan Scott, the Leader of the General Relativity Theory and Data Analysis Group at Australian National University (ANU), which played a key role in the observation.

It is also the loudest gravitational wave signal we’ve detected.

The collision occurred in a galaxy called NGC 4993, which lies about 130 million light-years away – that might sound far, but it’s much closer than previous observations, which occurred at distances of billions of light-years.

As well as producing gravitational waves, the neutron stars’ collision sent a host of electromagnetic signals sweeping across the universe, including a short gamma ray burst, X-rays, light and radio waves.

These were picked up by observatories all over the world, helping pinpoint the source.

ANU was among those, using SkyMapper and the Siding Spring Observatory in New South Wales, Australia, to observe the brightness and color of the light signals given off.

Along with learning more about gravitational waves, the discovery can teach astronomers about neutron stars.

Created when larger stars collapse, neutron stars are relatively tiny – only about 10 km (6.2 mi) wide – and incredibly dense, with very strong magnetic fields. Other than that, not a whole lot is known about them.

With this discovery we have the opportunity to learn so much more about neutron stars, which have been quite a mystery to us,” says Scott.

Unlike black holes, neutron star collisions emit other signals such as gamma rays, light and radio waves so astronomers around the world were able to observe the event through telescopes. This is an amazing time to be a scientist.

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Neptune’s Moon: Triton

We don’t know with what beverage William Lassell may have celebrated his discovery of Neptune’s moon, Triton, but beer made it possible.

Lassell was one of 19th century England’s grand amateur astronomers, using the fortune he made in the brewery business to finance his telescopes.

He spotted Triton on 10 October 1846 — just 17 days after a Berlin observatory discovered Neptune.

Curiously, a week before he found the satellite, Lassell thought he saw a ring around the planet. That turned out to be a distortion caused by his telescope.

But when NASA’s Voyager 2 visited Neptune in 1989, it revealed that the gas giant does have rings, though they’re far too faint for Lassell to have seen them.

Since Neptune was named for the Roman god of the sea, its moons were named for various lesser sea gods and nymphs in Greek mythology.

Triton (not to be confused with Saturn’s moon, Titan), is far and away the largest of Neptune’s satellites. Dutch-American astronomer Gerard Kuiper (for whom the Kuiper Belt was named) found Neptune’s third-largest moon, Nereid, in 1949.

He missed Proteus, the second-largest, because it’s too dark and too close to Neptune for telescopes of that era.

Proteus is a slightly non-spherical moon, and it is thought to be right at the limit of how massive an object can be before its gravity pulls it into a sphere.

Proteus and five other moons had to wait for Voyager 2 to make themselves known. All six are among the darker objects found in the solar system.

Astronomers using improved ground-based telescopes found more satellites in 2002 and 2003, bringing the known total to 13.

Voyager 2 revealed fascinating details about Triton. Part of its surface resembles the rind of a cantaloupe.

Ice volcanoes spout what is probably a mixture of liquid nitrogen, methane and dust, which instantly freezes and then snows back down to the surface.

One Voyager 2 image shows a frosty plume shooting 8 km (5 miles) into the sky and drifting 140 km (87 miles) downwind.

Triton’s icy surface reflects so much of what little sunlight reaches it that the moon is one of the coldest objects in the solar system, about -400 degrees Fahrenheit (-240 degrees Celsius).

Triton is the only large moon in the solar system that circles its planet in a direction opposite to the planet’s rotation (a retrograde orbit), which suggests that it may once have been an independent object that Neptune captured.

The disruptive effect this would have had on other satellites could help to explain why Nereid has the most eccentric orbit of any known moon it’s almost seven times as far from Neptune at one end of its orbit as at the other end.

Neptune’s gravity acts as a drag on the counter-orbiting Triton, slowing it down and making it drop closer and closer to the planet.

Millions of years from now, Triton will come close enough for gravitational forces to break it apart possibly forming a ring around Neptune bright enough for Lassell to have seen with his telescope.

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An Alphabet Soup Of Absurd Astronomy Acronyms

Astronomy loves acronyms. Some of them are evocative, charming, and memorable. Others are more laboured in their execution. This is an ode unusual acronyms, from the cleverly complex to the eye-rolling fail.

Acronyms are prevalent when talking about astronomy and space science.

In the past few months I’ve covered JPL, JAXA, OCO2, ISEE-3, SDO, IRIS, DSN, GRBs and UXOs, a whole host of CubeSats, DTMs, IRNSS-1B, GPM, DOVES, MRO, LADEE, SPHERES, and far, far too many other jumbles of letters to easily remember.

For the most part, they make handy tags for finding related articles later, but aren’t particularly memorable or meaningful to anyone outside the field.

I’ve always had a soft spot for the main competing theories for dark matter: MAssive Compact Halo Objects (MACHOs) and Weakly Interacting Massive Particles (WIMPs).

They thematically work, they have a bit of sass, and despite not being a practicing astrophysicist, I remember exactly what they stand for every time the topic comes up.

Best of all, I remember them as a linked set of concepts, a pair of theories related to the same mysterious phenomena. As far as acronyms go, that’s pretty much a perfect set of features.

Meanwhile, a few of the amazing instruments selected for the 2020 Mars rover have overly-laboured acronym-names, or, stranger still, awkward acronym-names that don’t actually match up with the extended phrases.

All my love to MOXIE, but it’s never a good sign when your acronym contains a nested acronym.

Then again, I once earnestly worked on BOOST, a component of BEAST as part of an alliterative investigation of the CMB (Cosmic Microwave Background), so I can’t tease too hard.

Astronomer and computer engineer Glen Petitpas at the Harvard-Smithsonian Center for Astrophysics has been collecting the other sort of acronyms.

You know the ones, where the acronym clearly came first and the name was awkwardly forced around it to fit, or are so thematically off-base that you don’t even know how scientists can write serious academic papers involving them without snickering.

Here’s a few of my so-bad-they’re-good favourites:

  • 5MUSES: 5 MegaJansky Unbiased Spitzer Extragalactic Survey is an instrument observing program for the Spitzer Space Telescope that picks up light somewhere between nearby spiral galaxies and Ultra Luminous Infrared Galaxies (ULIRGs, for a bonus acronym).
  • AMBER: Astronomical MultiBEam Recombiner is an instrument on the Very Large Telescope Interferometer used to blend beams from several telescopes into one signal. It’s also a cheater of an acronym for shamelessly plucks letters from the middle of words.
  • CANGAROO: Collaboration between Australian and Nippon for a Gamma Ray Observatory in the Outback, an international collaboration to look for gamma ray bursts that is just too cute for words.
  • FASTSOUND: FMOS Ankoku Shindou Tansa Subaru Observation Understanding Nature of Dark energy may be the definition of trying to hard with multilingual nested acronyms.
  • ARISTOTELES: Applications and Research Involving Space Technologies Observing the Earth’s field from Low Earth orbiting Satellite is not so much a name, as an entire sentence packed into a single word, cherry-picking whichever lead-letters fit the theme.
  • GADZOOKS! Gadolinium Antineutrino Detector Zealously Outperforming Old Kamiokande, Super! is a proposed/under-construction dedicated test facility near the Kamioka mine and Super Kamiokande detector. Yes, it has an exclamation point.

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The Solar System May Be Hosting A Visitor From The Stars

Yesterday, the Minor Planet Center has announced the discovery of a new comet, C/2017 U1, by the PanSTARRS survey.

It is quite faint and we would not talk about it, but it has something very unique. It is the first comet which, so far, likely comes from outside the Solar System.

“So far”, as this statement is based on a few tens of observations. Tenagra Observatories, now partner of the Virtual Telescope Project, observed it while it was waiting for confirmation.

On the discovery circular, Gareth V. Williams, Associate Director of the Minor Planet center, wrote: “Further observations of this object are very much desired.

Unless there are serious problems with much of the astrometry listed below, strongly hyperbolic orbits are the only viable solutions.

Although it is probably not too sensible to compute meaningful original and future barycentric orbits, given the very short arc of observations, the orbit below has e ~ 1.2 for both values.

If further observations confirm the unusual nature of this orbit, this object may be the first clear case of an interstellar comet”. All this sounds quite exciting.

Its orbit is hyperbolic, so it is not a closed one.

Bill Gray, on the Minor Planet Mailing List (MPML), mentioned that, assuming the available data, this comet should arrive from the Vega direction, but a connection with a given star is still not available.

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According To Stephen Hawking, We Have Less Than 100 Years To Save The Human Race

The human race is entering the most dangerous 100 years in its history and faces a looming existential battle, Stephen Hawking has warned.

The theoretical physicist identified artificial intelligence (AI), nuclear war and genetically-engineered viruses as just some of the man-made problems that pose an imminent threat to humanity.

And the 74-year-old said that as we rapidly advance in these fields, there will be “new ways things can go wrong”.

We are at a point in history where we are “trapped” by our own advances, with humanity increasingly at risk from man-made threats but without technology sophisticated enough to escape from Earth in the event of a cataclysm.

He warned: “Although the chance of a disaster to planet Earth in a given year may be quite low, it adds up over time, and becomes a near certainty in the next thousand or ten thousand years.

By that time we should have spread out into space, and to other stars, so a disaster on Earth would not mean the end of the human race.

However, we will not establish self-sustaining colonies in space for at least the next hundred years, so we have to be very careful in this period.

He added that humans do have a knack of “saving the day” just in time, and urged fellow scientists to continue trying to make advances in their respective fields.

Prof Hawking said: “We are not going to stop making progress, or reverse it, so we have to recognise the dangers and control them. I’m an optimist, and I believe we can.

It’s important to ensure that these changes are heading in the right directions. In a democratic society, this means that everyone needs to have a basic understanding of science to make informed decisions about the future.

So communicate plainly what you are trying to do in science, and who knows, you might even end up understanding it yourself.

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Gravitational Waves Just Led Us To The Incredible Origin Of Gold In The Universe

The Nobel Prize–winning Laser Interferometer Gravitational-Wave Observatory (LIGO) observatory has already changed the world of astronomy.

When the scientists in the LIGO collaboration announced the first detection of gravitational waves in 2016, it meant they’d discovered a new way to observe the universe.

For the first time, scientists could “listen” to ripples in spacetime created by the collision of massive objects like black holes.

But that was just the beginning. The dream, all along, was to combine gravitational wave detections with observations from more traditional telescopes.

On Monday, a team of thousands of LIGO scientists around the globe published an incredible finding spread throughout several papers in the journal Physical Review Letters.

Not only did these scientists detect, for the first time, the gravitational waves produced from two colliding neutron stars, but they were able to pinpoint their location in the sky and witness the event with optical and electromagnetic telescopes.

The gravitational waves tell physicists how large and how far away the objects are, and allow scientists to recreate the moments before they collided.

Then the observations in optical light and electromagnetic waves fill in the blanks that gravitational waves can’t answer.

They help astronomers nail down exactly what the objects were made out of, and which elements their collisions produced.

In this case, the scientists were able to conclude that the resulting explosion from a neutron star merger produces heavy elements like gold, platinum, and uranium.

On August 17 at 8:41 am, LIGO detected gravitational waves — literal distortions in space and time — passing through Earth.

LIGO is a pair of L-shaped observatories in Washington state and Louisiana that can detect when these waves temporarily squish and stretch the fabric of spacetime around us.

In the past two years, LIGO had detected gravitational waves generated by black holes that had crashed into one another.

When LIGO detects gravitational waves, it automatically sends out alerts to hundreds of scientists across the world. Brown was one of them.

We got on the phone very quickly, and we realized this was a very loud gravitational wave signal. It blew our socks off,” he says.

On the day of the gravitational wave detection, the scientists immediately got another clue that something big was happening.

Two seconds after LIGO detected the gravitational waves, Fermi, a NASA satellite, detected a gamma-ray burst, one of the most powerful explosions of energy we know of in the universe.

It had long been theorized that neutron star mergers could create gamma-ray bursts. This couldn’t be a coincidence.

But light from the neutron star merger and subsequent explosion would soon dim. And so the LIGO collaboration scientists were suddenly under intense pressure to move quickly.

The sooner you get telescopes on this thing, the more information you get,” Brown says.

Studying that light, and how it changes, would teach scientists a huge amount about neutron stars and how their collisions transform matter.

This discovery is so exciting because it means we’re truly in a new age of astronomy.

It means scientists can study celestial objects not just in terms of the light or radiation they emit they can also combine those observations with data from gravitational waves.

It means scientists have data on the entirety of this collision. They have data on how the two neutron stars danced around each other, they have data on the moment of impact, and they have extensive data on the aftermath.

Scientists expect to observe more black hole mergers, more neutron star mergers. But stranger, cooler observations may come through as well.

If LIGO and VIRGO continue to be upgraded, it’s possible they could detect gravitational waves still rippling away from the Big Bang.

Or, more excitingly, they could detect sources of gravitational waves that have never been predicted or observed.

I was a little sad I was not alive for the first moon landing,” Thomas Corbitt, a physicist and LIGO collaborator at Louisiana State University, says.

But when you see things like this, which are a testament to what people can do when they work together, it really is inspiring, and it teaches us about the universe.

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Half Of The Universe’s Missing Matter Has Been Found

Scientists have just found half of the universe’s missing matter in a landmark discovery.

Separate teams at the Institute of Space Astrophysics in Orsay, France, and the University of Edinburgh have finally discovered the missing links between galaxies after years of speculation.

The missing matter is made of particles called baryons which link galaxies together through filaments of hot, diffuse gas.

Previous observations in space had not picked the matter up because the gas is tenuous and not hot enough for X-ray telescopes.

But scientists believed there should be more normal matter out there than had been previously been discovered and set about to show the threads of gas actually exist.

Both groups found confirmation that the gas in the areas they were studying were dense enough to form filaments, ‘definitive’ evidence they existed between the galaxies.

Hideki Tanimura, leader of one of the groups in France said that the missing baryon problem had been solved.

Ralph Kraft at the Harvard-Smithsonian Center for Astrophysics in Massachusetts, added: “Everybody sort of knows that it has to be there, but this is the first time that somebody has come up with a definitive detection.

This goes a long way toward showing that many of our ideas of how galaxies form and how structures form over the history of the universe are pretty much correct.”

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A Super Massive Black Hole Has Been Spotted Snacking – Twice!

Normally dormant supermassive black holes do not give off any light or radiation as they are not actively devouring matter. They can only be indirectly observed by the pattern of stars around them.

But astronomers at the University of Maryland and the University of Michigan were able to observe x-rays bouncing around a disk of debris around a supermassive black hole called Swift J1644+57.

Sitting in the centre of a small galaxy in the Draco constellation about 3.8 billion light years away, the giant black hole appears to have woken from its slumber to destroy the star.

What remains of stars devoured by the black hole sit around it in a puffy cloud known as an accretion disk.

The X-rays given off by the star as it was torn apart have helped to illuminate this disk.

Dr. Erin Kara, an astronomer at the University of Maryland who was the lead author of the study, said: “Before this result, there was no clear evidence that we were seeing into the innermost regions of the accretion disk.”

We thought the emission was from the jet pointed at us, or further away and not close to central black hole.”

This new study shows us that, actually, we can see this reverberation at work very close to the central black hole.

The feeding frenzy that occurs when a star strays too close to a dormant star is known as a tidal disruption event. Occassionally these light up with x-rays.

The disk of debris acts like a reflective shield behind a flashlight bulb, reflecting and focusing the radiation given off.

Dr Kara said: “Most tidal disruption events don’t emit much in the high-energy X-ray band.

But there have been at least three known events that have, and this is the first and only such event that has been caught at its peak.”

Conventional wisdom among astronomers has long held that, during a tidal disruption event, high-energy X-rays are created further from the black hole in the relativistic jets – huge beams of particles ejected by the black hole and accelerated to nearly the speed of light.

But seeing X-ray emissions bouncing off the walls of the inner accretion disk has cast a new light on this assumption.

The team used X-ray reverberation mapping to chart out the inside of the accretion disk, much in the same way that sound waves can be used to map the seafloor or canyons by measuring the time delays of echoes.

The researchers, whose work is published in the journal Nature, computed small delays in the arrival time of X-ray signals reflected from iron atoms in the accretion disk.

Dr. Kara said: “We know how sound echoes in a large auditorium, for example. Because we know the speed of sound, we can use the time delay information to calculate the shape of the auditorium.

We are doing the same with X-ray radiation to map out the inner accretion disk. It’s a cool, novel technique that has only been developed within the last six years.

To date, most of what astronomers know about supermassive black holes comes from a handful of black holes that are actively gathering and consuming matter.

It is thought, however, that these account for just 10 per cent of the supermassive black holes in the universe.

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