Astrophysicists announce discovery that could rewrite story of how galaxies die

(THIS ARTICLE IS COURTESY OF PHYSICS.ORG)

 

Astrophysicists announce discovery that could rewrite story of how galaxies die

Astrophysicist announces her discovery that could rewrite story of how galaxies die
This artist conception depicts an energetic quasar which has cleared the center of the galaxy of gas and dust, and these winds are now propagating to the outskirts. Soon, there will be no gas and dust left, and only a luminous blue quasar will remain. Credit: Michelle Vigeant

At the annual meeting of the American Astronomical Society in St. Louis, Missouri, Allison Kirkpatrick, assistant professor of physics and astronomy at the University of Kansas, will announce her discovery of “cold quasars”—galaxies featuring an abundance of cold gas that still can produce new stars despite having a quasar at the center—a breakthrough finding that overturns assumptions about the maturation of galaxies and may represent a phase of every galaxy’s lifecycle that was unknown until now.

Her news briefing, entitled “A New Population of Cold Quasars,” takes place Wednesday, June 12, on the 2nd floor of the St. Louis Union Station Hotel.

A quasar, or “quasi-stellar radio source,” is essentially a  on steroids. Gas falling toward a quasar at the center of a galaxy forms an “accretion disk” which can cast off a mind-boggling amount of electromagnetic energy, often featuring luminosity hundreds of times greater than a typical galaxy. Typically, formation of a quasar is akin to galactic retirement, and it’s long been thought to signal an end to a galaxy’s ability to produce .

“All the gas that is accreting on the black hole is being heated and giving off X-rays,” Kirkpatrick said. “The wavelength of light that you give off directly corresponds to how hot you are. For example, you and I give off infrared light. But something that’s giving off X-rays is one of the hottest things in the universe. This gas starts accreting onto the black hole and starts moving at relativistic speeds; you also have a magnetic field around this gas, and it can get twisted up. In the same way that you get solar flares, you can have jets of material go up through these magnetic field lines and be shot away from the black hole. These jets essentially choke off the gas supply of the galaxy, so no more gas can fall on to the galaxy and form new stars. After a galaxy has stopped forming stars, we say it’s a passive dead galaxy.”

But in Kirkpatrick’s survey, about 10 percent of  hosting accreting supermassive  had a supply of cold gas remaining after entering this phase, and still made new .

Astrophysicist announces her discovery that could rewrite story of how galaxies die
An optical blue quasar at a lookback time of 7 billion years (this is not a nearby galaxy). Normally, something like this would not have infrared emission. Credit: Dark Energy Camera Legacy Survey DR7/NOAO

“That in itself is surprising,” she said. “This whole population is a whole bunch of different objects. Some of the galaxies have very obvious merger signatures; some of them look a lot like the Milky Way and have very obvious spiral arms. Some of them are very compact. From this diverse population, we then have a further 10 percent that is really unique and unexpected. These are very compact, blue, luminous sources. They look exactly like you would expect a supermassive black hole to look in the end stages after it has quenched all of the star formation in a galaxy. This is evolving into a passive elliptical galaxy, yet we have found a lot of cold gas in these as well. These are the population that I’m calling ‘cold quasars.'”

The KU astrophysicist suspected the “cold quasars” in her survey represented a brief period yet to be recognized in the end-phases of a galaxy’s lifespan—in terms of a human life, the fleeting “cold quasar” phase may something akin to a galaxy’s retirement party.

“These galaxies are rare because they’re in a transition phase—we’ve caught them right before star formation in the galaxy is quenched and this transition period should be very short,” she said.

Kirkpatrick first identified the objects of interest in an area of the Sloan Digital Sky Survey, the most detailed digital map of the universe available. In an area dubbed “Stripe 82,” Kirkpatrick and her colleagues were able to visually identify quasars.

“Then we went over this area with the XMM Newton telescope and surveyed it in the X-ray,” she said. “X-rays are the key signature of growing black holes. From there, we surveyed it with the Herschel Space Telescope, a far infrared telescope, which can detect dust and gas in the host galaxy. We selected the galaxies that we could find in both the X-ray and in the infrared.”

Astrophysicist announces her discovery that could rewrite story of how galaxies die
The dust emission of the same blue-quasar galaxy. It is surprisingly bright — in fact, it’s one of the brightest objects in the field, indicating a lot of dust. Due to the resolution of the telescope, we cannot see what that dust actually looks like. Credit: Herschel/ESA

The KU researcher said her findings give scientists new understanding and detail of how the quenching of star formation in galaxies proceeds, and overturns presumptions about quasars.

“We already knew quasars go through a dust-obscured phase,” Kirkpatrick said. “We knew they go through a heavily shrouded phase where dust is surrounding the supermassive black hole. We call that the red quasar phase. But now, we’ve found this unique transition regime that we didn’t know before. Before, if you told someone you had found a luminous quasar that had a blue optical color—but it still had a lot of dust and gas in it, and a lot of star formation—people would say, ‘No, that’s not the way these things should look.'”

Next, Kirkpatrick hopes to determine if the “cold quasar” phase happens to a specific class of galaxies or every galaxy.

“We thought the way these things proceed was you have a growing black hole, it’s enshrouded by dust and gas, it begins to blow that material out,” she said. “Then it becomes a luminous blue object. We assumed when it blew out its own gas, it would blow out its host gas as well. But it seems with these objects, that’s not the case. These have blown out their own dust—so we see it as a blue object—but they haven’t yet blown out all of the dust and gas in the host galaxies. This is a transition phase, let’s say of 10 million years. In universal timescales, that’s really short—and it’s hard to catch this thing. We’re doing what we call a blind survey to find objects we weren’t looking for. And by finding these objects, yes, it could imply that this happens to every galaxy.”

What planet was NASA’s Curiosity Rover sent to?

(THIS ARTICLE IS COURTESY OF TRIVIA GENIUS)

 

What planet was NASA’s Curiosity Rover sent to?

Venus

3%

Jupiter

9%

Mars

84%

Mercury

4%
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Launched in November 2011, the Curiosity Rover was sent to Mars to collect data and, hopefully, answer the question “Did Mars ever have the right conditions to support life?” Curiosity answered this question early on, when it discovered chemical and mineral evidence of past habitable environments on the Red Planet. Though other missions have been sent to Mars, Curiosity carries the most advanced scientific instruments of any of them and can travel farther on Mars’ surface due to increased power capacity.
Source: NASA | Date Updated: June 5, 2019
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The farthest-away manmade objects in space

Right now, somewhere in the world, children stand at the edge of a lake counting the hops of stones skidding across the surface of the water. It’s hard to explain the tranquil pleasure of watching the ripples emanate farther and farther till nearly out of sight, but it’s even more of a challenge to fathom the distances to which we’ve launched objects into the dark ocean of space. As of February 2018, the Voyager 1 drifts 13 billion miles away from the surface of the earth, 42 years since its launch. It is one of five man made objects that has ever left our solar system.

Pioneer 10

Credit: NASA.gov

Five years before the launch of the Voyager probes, on March 2, 1972, NASA launched the Pioneer 10 to investigate the surface of Jupiter. Weighing 569 pounds, the Pioneer 10 was the first spacecraft to cross the asteroid belt between Mars and Jupiter and, eventually, escape our solar system by nature of its velocity. It was also the first spacecraft to launch from the three-stage Atlas-Centaur launch vehicle to achieve its launch speed of 32,400 mph. It took the Pioneer 10 twelve weeks to cross the orbit of Mars. On December 3, 1973, the Pioneer 10 passed by the cloud tops of Jupiter to obtain the first close-up images of the planet.

Following its flyby of Jupiter, Pioneer 10 continued to gather data for NASA of the outer solar system until the end of its mission in March 31, 1977. The last faint signal from Pioneer 10 was received on January 23, 2003, as its radioisotope power source had decayed to the point of being unable to send further signals.

Pioneer 11

Credit: NASA.gov

The launch of Pioneer 10 was succeeded just a year later on April 5, 1973. The launch this time was accelerated by an additional 210 ft/sec and aimed to pass Jupiter at a point closer to its surface. The closer proximity to Jupiter caused the spacecraft to accelerate by gravitational pull to the muzzle velocity of a rifle (110,000 mph), allowing it to obtain the velocity and direction necessary to approach Saturn.

On September 1, 1979, Pioneer 11 flew to within 13,000 miles of Saturn to obtain the first close-up images of the planet and discover two previously-unobserved moons. By September of 1995, the spacecraft could no longer make observations and by November, the last communication with the spacecraft was made.

Voyager 1 & 2

Credit: NASA.gov

The Voyager spacecrafts were initially tasked with observing the properties and magnetospheres of our neighboring planets using their onboard instrumentation. Target planets included Jupiter, Saturn, and Saturn’s moon Titan. Data from the Pioneer 10 mission was used to create more robust spacecraft to tolerate the intense radiation around Jupiter. Voyager 1 started its observation of Saturn, the final phase of its initial mission, on August 22, 1980, whereas the Voyager 2 was sent on a longer trajectory to observe Uranus and Neptune, reaching Neptune on August 25, 1989.

In addition to their planetary observations, both Voyager spacecrafts were also tasked with interstellar missions. They were designed to continue scientific observations and signal transmission after escaping the heliosphere and exiting our solar system. They are both still active, with a projected lifetime of about five more years.

New Horizons

Credit: NASA.gov

In 2006, NASA launched the New Horizons spacecraft with a primary mission of observing the dwarf planet Pluto. New Horizons was launched as the fastest man-made object ever launched from Earth with a speed of 36,400 mph. New Horizons started its flyby of Pluto on July 14, 2015. Three years later, in August of 2018, it confirmed the existence of a hydrogen wall previously observed by the Voyager launch.

Black hole BOMBSHELL: NASA astronomer hints universe could be a HOLOGRAM

(THIS ARTICLE IS COURTESY OF THE UK EXPRESS NEWS)

 

Black hole BOMBSHELL: NASA astronomer hints universe could be a HOLOGRAM

BLACK holes could hold all of the secrets of the universe and prove once and for all we live in a “giant hologram”, a NASA astronomer has spectacularly claimed.

NASA claim that WATER is present on the moon’s surface

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Black holes are incredible wells of gravity, where the force of attraction traps everything including light. Black holes are often found at the hearts of galaxies and up until April this year have been purely theoretical. In April, astronomers behind the Event Horizon Telescope (EHT) collaboration photographed the first ever shadow of a black hole millions of light-years from Earth. But little is still known about the exact nature of these terrifying objects and speculation is rampant.

This is why astronomer Michelle Thaller, who is the assistant director of Science Communications at , said dark holes challenge our understanding of physics.

The  experts appeared in a science video for Big Think, where she discussed the idea black holes are key to cracking the secrets of the universe.

And perhaps most shockingly, the astronomer suggested the universe in which we live is nothing more than a two-dimensional hologram.

Dr Thaller said: “Things are stopped in time as they fell into the black hole. And right at the boundary, there is almost kind of a sphere, a two-dimensional surface that somehow contains all the information about what’s inside the black hole.

READ MORE: 

Black hole shock: The universe is a hologram

Black hole SHOCK: Black holes and the universe could be a hologram in a shock twist (Image: GETTY)

“And this reminds people of something that humans invented, called a hologram.

“Now, a hologram is a two-dimensional object. You can make it out of glass or a piece of film. And you shine a light through it and all of a sudden, there seems to be three-dimensional projections.

“And the idea is that we are looking at some fundamental way the universe stores information. Around a black hole, where space and time have been crushed out of existence, could there be a shell of information, something like a hologram?”

But how does this cosmic revelation suggest the universe at large is a form of a hologram?

READ MORE: 

According to Dr Thaller, black holes could be a miniaturised representation of how the universe works on a big scale.

This all sounds incredibly strange

Dr Michelle Thaller, NASA

In this scenario, all of the information in the universe is spread out across a 2D surface and we could be part of it.

But the astronomer said this does not in any way imply intent or creative design behind the hologram.

She said: “We’re just talking about the universe may really be information contained in a two-dimensional structure, not the three dimensions that we’re aware of now. This all sounds incredibly strange.

READ MORE: 

Black hole in space: Universe is a hologram

Black holes are incredible wells of gravity peppered throughout the cosmos (Image: GETTY)

Black hole: Dr Michelle Thaller

Black hole: Dr Michelle Thaller said the universe could be two-dimensional information (Image: BIG THINK)

“I’m always a little bit afraid to talk about it. But I think that the thing to really kind of gain from this is that black holes are staring us right in the face. We’re now observing them.

“They’re right there. And we cannot really describe how the universe should work with one of these things. They don’t make sense.”

On April 10, 2019, the EHT collaboration published the world’s first ever photograph of a distant black hole at the heart of galaxy Messier 87.

The historic achievement confirmed the existence of black holes 100 years after they were theorised by Albert Einstein’s theory of relativity and by astronomer Karl Schwarzschild.

Researchers wonder if ancient supernovae prompted human ancestors to walk upright

(THIS ARTICLE IS COURTESY OF PHYS.ORG)

 

Researchers wonder if ancient supernovae prompted human ancestors to walk upright

Researchers wonder if ancient supernovae prompted human ancestors to walk upright
A new paper from a University of Kansas researcher suggests bipedalism arose when ancient supernovae caused lightning that burned Earth’s forests and prompted human ancestors to walk upright. Credit: NASA

Did ancient supernovae induce proto-humans to walk on two legs, eventually resulting in homo sapiens with hands free to build cathedrals, design rockets and snap iPhone selfies?

A paper published today in the Journal of Geology makes the case: Supernovae bombarded Earth with cosmic energy starting as many as 8 million years ago, with a peak some 2.6 million years ago, initiating an avalanche of electrons in the lower atmosphere and setting off a chain of events that feasibly ended with bipedal hominins such as homo habilis, dubbed “handy man.”

The authors believe atmospheric ionization probably triggered an enormous upsurge in cloud-to-ground  that ignited  around the globe. These infernos could be one reason ancestors of  developed bipedalism—to adapt in savannas that replaced torched forests in northeast Africa.

“It is thought there was already some tendency for hominids to walk on two legs, even before this event,” said lead author Adrian Melott, professor emeritus of physics & astronomy at the University of Kansas. “But they were mainly adapted for climbing around in trees. After this conversion to savanna, they would much more often have to walk from one tree to another across the grassland, and so they become better at walking upright. They could see over the tops of grass and watch for predators. It’s thought this conversion to savanna contributed to bipedalism as it became more and more dominant in human ancestors.”

Based on a “telltale” layer of iron-60 deposits lining the world’s sea beds, astronomers have high confidence supernovae exploded in Earth’s immediate cosmic neighborhood—between 100 and only 50 parsecs (163 ) away—during the transition from the Pliocene Epoch to the Ice Age.

“We calculated the ionization of the atmosphere from  which would come from a supernova about as far away as the iron-60 deposits indicate,” Melott said. “It appears that this was the closest one in a much longer series. We contend it would increase the ionization of the lower atmosphere by 50-fold. Usually, you don’t get lower-atmosphere ionization because cosmic rays don’t penetrate that far, but the more energetic ones from supernovae come right down to the surface—so there would be a lot of electrons being knocked out of the atmosphere.”

According to Melott and co-author Brian Thomas of Washburn University, ionization in the lower atmosphere meant an abundance of electrons would form more pathways for lightning strikes.

“The bottom mile or so of atmosphere gets affected in ways it normally never does,” Melott said. “When high-energy cosmic rays hit atoms and molecules in the atmosphere, they knock electrons out of them—so these electrons are running around loose instead of bound to atoms. Ordinarily, in the lightning process, there’s a buildup of voltage between clouds or the clouds and the ground—but current can’t flow because not enough electrons are around to carry it. So, it has to build up high voltage before electrons start moving. Once they’re moving, electrons knock more electrons out of more atoms, and it builds to a lightning bolt. But with this ionization, that process can get started a lot more easily, so there would be a lot more lightning bolts.”

The KU researcher said the probability that this lightning spike touched off a worldwide upsurge in wildfires is supported by the discovery of carbon deposits found in soils that correspond with the timing of the cosmic-ray bombardment.

“The observation is that there’s a lot more charcoal and soot in the world starting a few million years ago,” Melott said. “It’s all over the place, and nobody has any explanation for why it would have happened all over the world in different climate zones. This could be an explanation. That increase in fires is thought to have stimulated the transition from woodland to savanna in a lot of places—where you had forests, now you had mostly open grassland with shrubby things here and there. That’s thought to be related to human evolution in northeast Africa. Specifically, in the Great Rift Valley where you get all these hominin fossils.”

Melott said no such event is likely to occur again anytime soon. The nearest star capable of exploding into a supernova in the next million years is Betelgeuse, some 200 parsecs (652 light years) from Earth.

“Betelgeuse is too far away to have effects anywhere near this strong,” Melott said. “So, don’t worry about this. Worry about solar proton events. That’s the danger for us with our technology—a solar flare that knocks out electrical power. Just imagine months without electricity.”


Explore further

Research increases distance at which supernova would spark mass extinctions on Earth


More information: Journal of GeologyDOI: 10.1086/703418

750 FT asteroid barreling towards an Earth APPROACH at 18,800MPH

(THIS ARTICLE IS COURTESY OF THE UK EXPRESS NEWS)

 

NASA asteroid tracker: A 750 FT asteroid barreling towards an Earth APPROACH at 18,800MPH

AN ASTEROID nearly twice as tall as the Great Pyramid of Giza is hurtling in Earth’s direction at more than 18,800mph, NASA’s asteroid trackers have revealed.

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The -tracked asteroid, dubbed Asteroid 2011 HP, is flying towards our planet on a so-called Earth Close Approach trajectory. NASA predicts the imposing space rock will shoot past Earth on the morning of Thursday, May 30. According to NASA’ Jet Propulsion Laboratory (JPL), the asteroid will approach the planet around 11.48am BST or 6.48am Eastern Time. When this happens, NASA said the asteroid will break speeds of around 8.43km per second or 18,857.4mph (30,348kmh).

Asteroid HP is an Apollo-type Near-Earth  (NEA) or Near-Earth Object (NEO).

NASA’s JPL estimates the space rock measures somewhere in the range of 328ft to 754.6ft (100m to 230m) in diameter.

At the upper end of that scale, the asteroid is as tall as the Golden Gate Bridge in San Francisco, US, and the Space Needle in Seattle.

However, even at the lower end of the estimate, the space rock is still almost as tall as Big Ben’s clock tower in London, UK.

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NASA asteroid tracker: Giant space rock over Earth

NASA asteroid tracker: A colossal space rock will zip past the Earth on Thursday, May 30 (Image: GETTY)

The space rock orbits the inner circles of the solar system on a trajectory similar to that of asteroid 1862 Apollo.

The asteroid’s trajectory takes it beyond the orbit of Mars but it does not fly past the Asteroid Belt in-between Mars and the gas giant Jupiter.

All NEOs are comets and asteroids on paths, which orbit the Sun from distances smaller than 1.3 astronomical units or 120.8 million miles (194.5 million km).

One astronomical unit measures approximately 93 million miles (149.6 million km) – the distance from the Earth to the Sun.

READ MORE: 

Next week, Asteroid HP will significantly cut this distance down to around 0.03149 astronomical units.

Near-Earth Objects can occasionally approach close to Earth

NASA

This means the asteroid will near-miss the Earth from a distance of just 2.92 million miles (4.7 million km).

In other words, the  rock will approach our home-world 12.26 times as far as the Moon is.

NASA said: “As they orbit the Sun, Near-Earth Objects can occasionally approach close to Earth.

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NASA asteroid tracker: Giant space rock over Earth

NASA asteroid tracker: The asteroid was discovered on April 13, 2011 (Image: GETTY)

NASA asteroid tracker: Giant space rock over Earth

NASA asteroid tracker: Thankfully, the space rock will not hit the Earth and pass safely (Image: GETTY)

“Note that a ‘close’ passage astronomically can be very far away in human terms: millions or even tens of millions of kilometres.”

After the asteroid ups past the Earth next week, NASA predicts HP will visit us again on May 17, 2027.

Then, the space rock will make many more approaches every few years until September 2, 2184.

NASA asteroid trackers first observed the asteroid on April 13, 2011.

“Enormous Ghost Galaxy” –Hidden In the Milky Way’s ‘Zone of Avoidance’

(THIS ARTICLE IS COURTESY OF THE DAILY GALAXY)

 

“Enormous Ghost Galaxy” –Hidden In the Milky Way’s ‘Zone of Avoidance’ (Weekend Feature)

Milky Way Galactic Center

 

An enormous ‘ghost’ galaxy, believed to be one of the oldest in the universe, was detected lurking on the outskirts of the Milky Way in November of 2018 by a team of astronomers who discovered the massive object when trawling through new data from the European Space Agency’s Gaia satellite. The object, named Antlia 2, avoided detection thanks to its extremely low density as well as a perfect hiding place in the Zone of Avoidance, behind the shroud of the Milky Way’s disc–a region full of dust and an overabundance of bright stars near the galactic center.

“This is a ghost of a galaxy,” said Gabriel Torrealba, an astrophysicist at Taiwan’s Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) and the paper’s lead author. “Objects as diffuse as Ant 2 have simply not been seen before. Our discovery was only possible thanks to the quality of the Gaia data.” Gaia is able to dig into the Zone of Avoidance, he says, because it provides high-quality proper motions of stars behind the central disk of our Milky Way galaxy. That is, it is able to track stars as they move across the celestial sphere.

Optically, the Zone of Avoidance is like “trying to look through a velvet cloth—black as black can be,” says Thomas Dame, Director of the Radio Telescope Data Center at the Harvard-Smithsonian Center for Astrophysics and Senior Radio Astronomer at the Smithsonian Astrophysical Observatory. “In terms of tracing and understanding the spiral structure, essentially half of the Milky Way is terra incognito.”

“It’s the most Important thing in astrophysics”–the ‘Holy Grail’ of astronomy is to provide a clear perspective of our relationship to the physical universe. The map of our Milky Way galaxy is a part of that, a map that is still incomplete. Our solar system drifts between two spiral arms at its outer edges, some 27,000 light-years from its center. Beyond that, like the ancient sea-faring mariners, no space craft has ever traveled beyond the opaque central disk to turn back and take its picture.

“Monsters & Dragons?” –Mapping the Terra Incognito of Milky Way’s Unseen Far Side

“The zone of avoidance is basically the part of the sky obscured by the Milky Way’s disk as seen from the Earth,” said Torrealba. “The disk of the Milky Way has a lot of gas and stars, making it extremely crowded and complex.” But the team was able to use about a hundred old and metal-poor pulsating, so-called ‘RR Lyrae’ stars to probe inside and ultimately identify Antlia 2.

Optically, penetrating the Zone of Avoidance is like “trying to look through a velvet cloth—black as black can be,” says Thomas Dame, Director of the Radio Telescope Data Center at the Harvard-Smithsonian Center for Astrophysics and Senior Radio Astronomer at the Smithsonian Astrophysical Observatory. “In terms of tracing and understanding the spiral structure, essentially half of the Milky Way is terra incognito.”

“It’s the most Important thing in astrophysics”–the ‘Holy Grail’ of astronomy is to provide a clear perspective of our relationship to the physical universe. The map of our Milky Way galaxy is a part of that, a map that is still incomplete. Our solar system drifts between two spiral arms at its outer edges, some 27,000 light-years from its center. Beyond that, like the ancient sea-faring mariners, no space craft has ever traveled beyond the opaque central disk to turn back and take its picture.

Swarm of Faint Dwarf Galaxies Orbit the Milky Way –“Many More Hidden, Yet to Be Discovered”

“Compared to the rest of the 60 or so Milky Way satellites, Ant 2 is an oddball,” said co-author Matthew Walker, also from Carnegie Mellon University. “We are wondering whether this galaxy is just the tip of an iceberg, and the Milky Way is surrounded by a large population of nearly invisible dwarfs similar to this one.”

 

Antlia2 Dwarf Galaxy

 

Torrealba says that Antlia 2 is likeliest one of the oldest dwarf galaxies in the universe, but he and colleagues are still puzzled as to how it became so diffuse. “One possibility is that Antlia 2 was much more massive in the past, and as it fell into the Milky Way, it lost its mass to become more diffuse,” said Torrealba. One problem with this idea says Torrealba is that rather than grow, galaxies tend to shrink at the same time they lose stars.

Extreme Disk Galaxy Discovered –“Seven Times the Width of the Milky Way”

The object’s giant size, says astronomer Sergey Koposov at Carnegie Mellon University presents a puzzle, agreeing with Torrealba. “Normally, as galaxies lose mass to the Milky Way’s tides, they shrink, not grow.”

“Another possible explanation of the extraordinary appearance of Antlia 2,” Koposov wrote in an email to dailygalaxy.com, “is that there is something wrong with currently favored Cold Dark Matter theory that predicts that dark matter should be tightly packed in centers of galaxies. If dark matter distribution however is more fluffy, that can make it easier to form galaxies like Antlia 2,” he added.

Ant 2 is known as a dwarf galaxy. As structures emerged in the early Universe, dwarfs were the first galaxies to form, and so most of their stars are old, low-mass and metal-poor. But compared to the other known dwarf satellites of our Galaxy, Ant 2 is immense: it is as big as the Large Magellanic Cloud (LMC), and a third the size of the Milky Way itself.

What makes Ant 2 even more unusual is how little light it gives out. Compared to the LMC, another satellite of the Milky Way, Ant 2 is 10,000 times fainter. In other words, it is either far too large for its luminosity or far too dim for its size.

The ESA’s Gaia mission has produced the richest star catalog to date, including high-precision measurements of nearly 1.7 billion stars and revealing previously unseen details of our home Galaxy. Earlier in 2018, Gaia’s second data release made new details of stars in the Milky Way available to scientists worldwide.

The researchers behind the current study – from Taiwan, the UK, the US, Australia and Germany – searched the new Gaia data for Milky Way satellites by using RR Lyrae stars. These stars are old and metal-poor, typical of those found in a dwarf galaxy. RR Lyrae change their brightness with a period of half a day and can be located thanks to these well-defined pulses.

“RR Lyrae had been found in every known dwarf satellite, so when we found a group of them sitting above the Galactic disc, we weren’t totally surprised,” said co-author Vasily Belokurov from Cambridge’s Institute of Astronomy. “But when we looked closer at their location on the sky it turned out we found something new, as no previously identified object came up in any of the databases we searched through.”

The team contacted colleagues at the Anglo-Australian Telescope (AAT) in Australia, but when they checked the coordinates for Ant 2, they realized they had a limited window of opportunity to get follow-up data. They were able to measure the spectra of more than 100 red giant stars just before the Earth’s motion around the Sun rendered Ant 2 unobservable for months.

The spectra enabled the team to confirm that the ghostly object they spotted was real: all the stars were moving together. Ant 2 never comes too close to the Milky Way, always staying at least 40 kiloparsecs (about 130,000 light-years) away. The researchers were also able to obtain the galaxy’s mass, which was much lower than expected for an object of its size.

If it is impossible to puff the dwarf up by removing matter from it, then Ant 2 had to have been born huge. The team has yet to figure out the exact process that made Ant 2 so extended. While objects of this size and luminosity have not been predicted by current models of galaxy formation, recently it has been speculated that some dwarfs could be inflated by vigorous star formation. Stellar winds and supernova explosions would push away the unused gas, weakening the gravity that binds the galaxy and allowing the dark matter to drift outward as well.

“Even if star formation could re-shape the dark matter distribution in Ant 2 as it was put together, it must have acted with unprecedented efficiency,” said co-author Jason Sanders, also from Cambridge.

Alternatively, Ant 2’s low density could mean that a modification to the dark matter properties is needed. The currently favored theory predicts dark matter to pack tightly in the centers of galaxies. Given how fluffy the new dwarf appears to be, a dark matter particle which is less keen to cluster may be required.

The gap between Ant 2 and the rest of the Galactic dwarfs is so wide that this may well be an indication that some important physics is missing in the models of dwarf galaxy formation. Solving the Ant 2 puzzle may help researchers understand how the first structures in the early universe emerged.

The Daily Galaxy via Imperial College London

NASA: A MONSTROUS 1,280FT asteroid is headed towards Earth at 58,250MPH

(THIS ARTICLE IS COURTESY OF THE UK’S EXPRESS NEWS)

 

NASA asteroid tracker: A MONSTROUS 1,280FT asteroid is headed towards Earth at 58,250MPH

AN ASTEROID hurtling towards the Earth at nearly 58,250mph (93,744 kmh) is expected to fly over our planet next week, NASA’s asteroid trackers have revealed.

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The imposing , dubbed by NASA Asteroid 2019 JB1, is headed towards the Earth on a “Close Approach” trajectory. NASA’s asteroid trackers have calculated a close flyby in the early morning hours of Monday, May 20. According to NASA’s Jet Propulsion Laboratory (JPL) in California, Asteroid JB1 will shoot past our planet around 4.23am BST (3.23am UTC). And when the asteroid nears the Earth, it will reach breakneck speeds of around 26.04km per second or 58,349.8mph.

Asteroid JB1 is an Apollo-type “Near-Earth Object” or NEO asteroid.

NEOs are all asteroids and comets in orbit of the Sun at a distance of 1.3 astronomical units (au).

Just one astronomical unit measures about 93 million miles (149.6 million km), which is the distance between the Earth and the Sun.

’s JPL estimates JB1 measures somewhere in the range of 557.7ft to 1,279.5ft (170m to 390m) across.

READ MORE: 

NASA asteroid tracker: Giant space rock over Earth

NASA asteroid tracker: A giant space rock will fly past Earth on May 20 (Image: GETTY)

An asteroid at the upper end of the estimate is taller than the Eiffel Tower in Paris, France.

The asteroid is also about 200 times longer than a Queen Size bed and 45 London double-decker buses.

If the  rock were to hit the Earth, the force of impact could be cataclysmically deadly.

NASA said: “If a rocky meteoroid larger than 25m but smaller than one kilometre – a little more than 1/2 miles – were to hit Earth, it would likely cause local damage to the impact area.

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“We believe anything larger than one to two kilometres – one kilometre is a little more than one-half mile – could have worldwide effects.”

Anything larger than one to two kilometres could have worldwide effects

NASA

So, is there anything to fear from the asteroid’s flyby next week?

Thankfully, NASA predicts the asteroid will not come close enough to slam into the Earth.

At its closest, Asteroid JB1 will fly past Earth from a distance of 0.04305 astronomical units.

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This means Asteroid will come within four million miles (6.4 million km) of our home-world.

In other words, NASA expects the asteroid to fly by 16.76 times as far as the Moon is.

NASA explained: “As they orbit the Sun, Near-Earth Objects can occasionally approach close to Earth.

“Note that a ‘close’ passage astronomically can be very far away in human terms: millions or even tens of millions of kilometres.”

NASA asteroid tracker: Giant space rock over Earth

NASA asteroid tracker: The space rock will fly by at breakneck speeds (Image: GETTY)

NASA asteroid tracker: Giant space rock over Earth

NASA asteroid tracker: The space rock will pass the Earth safely without hitting (Image: GETTY)

Quick facts about asteroids:

1. Asteroids are the rocky remnants of the early solar system from an approximate 4.6 billion years ago.

2. NASA estimates there are currently 795,070 space rocks orbiting our Sun.

3. The biggest “potentially hazardous” asteroid NASA is aware of is the 3.35-mile-wide (5.4km) Toutatis.

4. NASA has established a Planetary Defense Coordination Office to keep the Earth safe from dangers of asteroid impacts.

5. Most of the asteroids we know of are in the so-called Asteroid Belt between Mars and Jupiter.

Astronomers discover third planet in the Kepler-47 circumbinary system

(THIS ARTICLE IS COURTESY OF PHYS.ORG)

 

Astronomers discover third planet in the Kepler-47 circumbinary system

Astronomers discover third planet in the Kepler-47 circumbinary system
Artistic rendition of the Kepler-47 circumbinary planet system. The three planets with the large middle planet being the newly discovered Kepler47d. Credit: NASA/JPLCaltech/T. Pyle

Astronomers have discovered a third planet in the Kepler-47 system, securing the system’s title as the most interesting of the binary-star worlds. Using data from NASA’s Kepler space telescope, a team of researchers, led by astronomers at San Diego State University, detected the new Neptune-to-Saturn-size planet orbiting between two previously known planets.

With its three planets orbiting two suns, Kepler-47 is the only known multi-planet circumbinary system. Circumbinary planets are those that orbit two stars.

The planets in the Kepler-47 system were detected via the “transit method.” If the orbital plane of the planet is aligned edge-on as seen from Earth, the planet can pass in front of the host stars, leading to a measurable decrease in the observed brightness. The new planet, dubbed Kepler-47d, was not detected earlier due to weak transit signals.

As is common with circumbinary planets, the alignment of the orbital planes of the planets change with time. In this case, the middle planet’s orbit has become more aligned, leading to a stronger transit signal. The transit depth went from undetectable at the beginning of the Kepler Mission to the deepest of the three planets over the span of just four years.

The SDSU researchers were surprised by both the size and location of the new planet. Kepler-47d is the largest of the three planets in the Kepler-47 system.

“We saw a hint of a third planet back in 2012, but with only one transit we needed more data to be sure,” said SDSU astronomer Jerome Orosz, the paper’s lead author. “With an additional transit, the planet’s orbital period could be determined, and we were then able to uncover more transits that were hidden in the noise in the earlier data.”

William Welsh, SDSU astronomer and the study’s co-author, said he and Orosz expected any additional planets in the Kepler-47 system to be orbiting exterior to the previously known planets. “We certainly didn’t expect it to be the largest planet in the system. This was almost shocking,” said Welsh. Their research was recently published in the Astronomical Journal.

Astronomers discover third planet in the Kepler-47 circumbinary system
Artistic rendition of the Kepler-47 circumbinary planet system. An overhead view of the orbital configuration. Credit: NASA/JPLCaltech/T. Pyle

With the discovery of the new planet, a much better understanding of the system is possible. For example, researchers now know the planets in in this circumbinary system are very low density – less than that of Saturn, the Solar System planet with the lowest density.

While a low density is not that unusual for the sizzling hot-Jupiter type exoplanets, it is rare for mild-temperature planets. Kepler-47d’s equilibrium temperature is roughly 50 degrees F (10 degrees C), while Kepler-47c is 26 degrees F ( 32 degrees C). The innermost planet, which is the smallest circumbinary planet known, is a much hotter 336 degrees F (169 degrees C).

The inner, middle, and outer planets are 3.1, 7.0, and 4.7 times the size of the Earth, and take 49, 187, and 303 days, respectively, to orbit around their suns. The stars themselves orbit each other in only 7.45 days; one star is similar to the Sun, while the other has a third of the mass of the Sun. The entire system is compact and would fit inside the orbit of the Earth. It is approximately 3340 light-years away in the direction of the constellation Cygnus.

“This work builds on one of the Kepler’s most interesting discoveries: that systems of closely-packed, low-density planets are extremely common in our galaxy,” said University of California, Santa Cruz astronomer Jonathan Fortney, who was not part of the study. “Kepler 47 shows that whatever process forms these planets – an outcome that did not happen in our solar system – is common to single-star and circumbinary planetary systems.”

Correction: A prior version of this article contained inaccuracies regarding the orbits of the Kepler-47 planets. This article has been updated to reflect the correct number of days it takes the inner, middle, and outer planets to orbit their suns: 49, 187 and 303 days respectively.


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More information: Jerome A. Orosz et al. Discovery of a Third Transiting Planet in the Kepler-47 Circumbinary System, The Astronomical Journal(2019). DOI: 10.3847/1538-3881/ab0ca0 , iopscience.iop.org/article/10. … 847/1538-3881/ab0ca0

Journal information: Astronomical Journal

NASA’s Curiosity rover digs up clay samples – Is it PROOF of water on Mars?

(THIS ARTICLE IS COURTESY OF THE U.K.’S ‘EXPRESS’ NEWS)

 

Life on Mars: NASA’s Curiosity rover digs up clay samples – Is it PROOF of water on Mars?

NASA’s Curiosity rover is drilling into the Red Planet to collect samples of Martian clay, which scientists believed formed in the presence of water – but could this also help find life on Mars?

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’s lonely Mars rover has successfully retrieved its first batch of soil from a “clay-bearing unit” near Mars’ Mount Sharp region. The US space agency has targeted this part of Mars for a drilling mission even before Curiosity blasted off towards the planet in November 2011. NASA has now confirmed Curiosity retrieved samples of bedrock material from a rock dubbed Aberlady on Sunday, April 6. The rover then delivered the soil samples to its onboard laboratory equipment on April 10 and scientists are waiting for the analysis results with bated breath.

Water is one of the most fundamental building blocks of life by human standards and is key to discovering alien life in other parts of the cosmos.

Scientists have long suspected Mars once hosted a lush and wet atmosphere with a landscape not too different from that of Earth’s.

Today, however, the planet is a harsh and inhospitable desert with a paper-thin atmosphere blasted by intense solar radiation.

The only signs of water present on Mars have been found in the form of ice caps around the freezing south pole.

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Life on Mars: NASA Curiosity rover drilling clay

Life on Mars: Curiosity is drilling out samples of clay from Martian bedrock (Image: NASA)

But the presence of clay in Martian soil promises to update NASA’s understanding of Mars’s ancient past.

And the results of the rover’s drilling operation so far appear to be promising.

Jim Erickson of NASA’s Jet Propulsion Laboratory said: “Curiosity has been on the road for nearly seven years.

“Finally drilling at the clay-bearing unit is a major milestone in our journey up Mount Sharp.”

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According to NASA, the remote rover’s drill “chewed easily” through the Martian rock, suggesting the bedrock was much softer than expected.

The space agency said in a statement: “It was so soft, in fact, that the drill didn’t need to use its percussive technique, which is helpful for snagging samples from harder rock.

“This was the mission’s first sample obtained using only rotation of the drill bit.”

However, it is unlikely the drilling mission will provide any major breakthrough in the hunt for liquid water.

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Life on Mars: NASA Curiosity rover on Mars

Life on Mars: Clay samples could be proof of ancient water could boost hopes of finding ancient life (Image: NASA)

Instead, NASA expects to learn more about how ancient waters helped shaped the three-mile-tall (five kilometres) Mount Sharp.

Finally drilling at the clay-bearing unit is a major milestone

Jim Erickson, NASA

NASA said Curiosity has so far encountered clay minerals and mudstones at every step of its journey through Mars.

These rocks are believed to have formed in ancient lakebeds by settling river sediments some 3.5 billion years ago.

The space agency said: “As with water elsewhere on Mars, the lakes eventually dried up.”

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And Ashwin Vasavada, a JPL Curiosity scientist said: “Each layer of this mountain is a puzzle piece. They each hold clues to a different era in Martian history.

“We’re excited to see what this first sample tells us about the ancient environment, especially about water.”

But what does all of this mean for the potential to find life on Mars?

Scientists widely agree life here on Earth started in water and it is water, which made life on Earth possible.

Life on Mars: Martian clay bedrock

Life on Mars: The remote rover drilled into this soft bed of exposed Martian rock (Image: NASA)

And if scientists can prove the same conditions once existed on Mars, the probability simple, single-celled life evolved on Mars will skyrocket.

NASA said: “Whether the water is boiling hot or frozen, some sort of creature seems to thrive in it. Is it the same on other planets?

“If water once flowed on Mars, did life once thrive there too? Or, maybe there is still water on Mars, only it has gone underground.

“Could there be tiny life forms—like bacteria—on Mars even now?”

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Was there ever life on Mars in the past?

If NASA’s scientists can prove Mars once hosted liquid lakes and rives, the next question is whether the conditions were ripe for microbial life to develop.

NASA said: “Is there any evidence of life in the planet’s past? If so, could any of these tiny living creatures still exist today?

“Imagine how exciting it would be to answer, ‘Yes!’”

Ellen Stofan, head of the Smithsonian’s Air and Space Museum in Washington DC, has argued before the US Senate .

She said: “Life rose here on Earth rapidly once conditions stabilised, so you know, for the first several hundred million years on Earth the conditions were probably hostile.

“It was as soon as conditions stabilised within 100 million years or so we are fairly confident that the first microbial life evolved on Earth.

“The problem is life remained in the oceans for a billion years and it took well over a billion years for life to gain any complexity. That’s why I’m optimistic life did evolve on Mars.”

Hubble Peers At Cosmic Blue Bauble

(THIS ARTICLE IS COURTESY OF PHYSICS.ORG AND NASA)

 

Hubble peers at cosmic blue bauble

Hubble peers at cosmic blue bauble
Messier 3: Containing an incredible half-million stars, this 8-billion-year-old cosmic bauble is one of the largest and brightest globular clusters ever discovered. Credit: ESA/Hubble & NASA, G. Piotto et al.

Globular clusters are inherently beautiful objects, but the subject of this NASA/ESA Hubble Space Telescope image, Messier 3, is commonly acknowledged to be one of the most beautiful of them all.

Containing an incredible half-million stars, this 8-billion-year-old cosmic bauble is one of the largest and brightest  ever discovered. However, what makes Messier 3 extra special is its unusually large population of variable stars—stars that fluctuate in brightness over time. New variable stars continue to be discovered in this sparkling stellar nest to this day, but so far we know of 274, the highest number found in any globular cluster by far. At least 170 of these are of a special variety called RR Lyrae variables, which pulse with a period directly related to their intrinsic brightness. If astronomers know how bright a star truly is based on its  and classification, and they know how bright it appears to be from our viewpoint here on Earth, they can thus work out its distance from us. For this reason, RR Lyrae stars are known as standard candles—objects of known luminosity whose  and position can be used to help us understand more about vast celestial distances and the scale of the cosmos.

Messier 3 also contains a relatively high number of so-called , which are shown quite clearly in this Hubble image. These are blue main sequence stars that appear to be young because they are bluer and more luminous than other stars in the . As all stars in globular clusters are believed to have formed together and thus to be roughly the same age, only a difference in mass can give these  a different color. A red, old star can appear bluer when it acquires more mass, for instance by stripping it from a nearby star. The extra mass changes it into a bluer star, which makes us think it is younger than it really is.


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