A ‘tsunami’ for astrophysics: New Gaia data reveals the best map of our galaxy yet

Astronomers were hit today (Dec. 3) with a huge wave of data from the European Space Agency’s Gaia space observatory.

Those researchers can now explore the best-yet map of the Milky Way, with detailed information on the positions, distances and motion of 1.8 billion cosmic objects, to help us better understand our place in the universe. 

“Gaia data is like a tsunami rolling through astrophysics,” said Martin Barstow, head of the physics and astronomy department at the University of Leicester, who is part of Gaia’s data processing team. He was speaking at a virtual news conference held today, at which another Gaia researcher, Giorgia Busso of the Leiden Observatory in the Netherlands, also told reporters that this data has produced “a revolution” in many fields of astrophysics, from the study of galactic dynamics like stellar evolution to the study of nearby objects like asteroids in the solar system.

Photos: Gaia spacecraft to map Milky Way galaxy

Gaia launched in December 2013 to map the galaxy in unprecedented detail. The $1 billion spacecraft orbits the Lagrange-2, or L2, point, a spot about 1 million miles (1.5 million kilometers) away from Earth, where the gravitational forces between our planet and the sun are balanced and the view of the sky is unobstructed. Gaia can measure about 100,000 stars each minute, or 850 million objects each day, and can scan the whole sky about once every two months. 

The latest trove of data improves upon the precision and scope of the two previous Gaia data sets, which were released in 2016 and 2018. For example, compared to the 2018 data, which included measurements for 1.7 billion objects, the 2020 data improves by a factor of two the accuracy of the data points for proper motion, or the apparent change in the position of a star as viewed from our solar system.

“It really gives us an insight into how the Milky Way lives,” Nicholas Walton, an astronomer at the University of Cambridge who is part of Gaia’s science team, said at the same science and news conference. “We’re talking about billions of stars, which really gives us the ability to probe at a meaningful level the whole population of the Milky Way, similar to what you’d want to do with studying people.” 

Walton said the cosmic census would be like having trackers on every person in the U.K. to map their location and monitor their health. “If everyone’s got a tracker, we could tell you if they’re sweating or not. It’s a bit like that with the stars here: We can tell you which ones are sweating, which ones are active, which ones are dormant, which ones are going to die, which ones are going to explode.”

Data from Gaia has already been used across a wide range of applications over the past four years. The mission has helped researchers find the corpse of a galaxy that the Milky Way cannibalized 10 billion years ago, spot 20

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The cutest Mars rover in the galaxy is one you can build for yourself

This perky little rover uses 3D-printed parts and runs on a Raspberry Pi computer.


ESA

Most Mars rovers are kind of cute anyway (hello, NASA Curiosity), but they’re about to be outdone by a new kid on the block: the ExoMy rover, a model Mars vehicle you can build for yourself from 3D-printed components.

ExoMy is based on the Rosalind Franklin ExoMars rover from the European Space Agency. ESA has made the ExoMy open-source plans available free online through GitHub.

“We focused on making the design as affordable and accessible as possible,” ESA’s Miro Voellmy said in a statement on Monday. “It uses a Raspberry Pi computer and off-the-shelf electronic parts available online and at any hobby shop.”  

The agency estimates it will cost between $300 and $600 to make the rover, which stands about 16 inches (42 centimeters) tall. 

ExoMy looks a lot like its full-size counterpart. It has six wheels and borrows the “triple-bogie” suspension that will allow Rosalind Franklin to handily navigate the rough terrain on Mars. The camera mast has a customizable face and is designed to wear different hats, just in case you want it to look even cuter.

ESA released a video of an ExoMy in action showing the little vehicle rolling over rocks and sand. “ExoMy is more than a toy as it can serve as a low-cost research and prototyping platform for robotic experiments,” said Voellmy.   

Rosalind Franklin was originally scheduled to launch in 2020, but technical issues and the coronavirus pandemic delayed it to 2022

Mars is set to become a busy place over the next few years. NASA, China and the United Arab Emirates all launched missions to the red planet this year, and all will arrive in February 2021. NASA and China will attempt to land rovers on the surface. 

ESA may have to wait a bit for Rosalind Franklin to catch up, but Earth could end up as home to plenty of plucky ExoMy rovers in the meantime. 

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NASA’s Hubble Spots Galaxy Being Stripped Of Dark Matter

Dark matter theory has long been sacrosanct in mainstream astronomical circles. Rarely do astronomers contradict the tenet that some 85 percent of all matter in the cosmos is dominated by unseen matter that only weakly interacts with gravity.   

Thus, it came as a surprise that doubt was cast on its existence by recent Hubble Space Telescope observations of two massive galaxies that appeared to be altogether devoid of this exotic matter. 

But in a paper submitted to The Astrophysical Journal, an international team of scientists detail observations on NGC 1052-DF4, the second galaxy purported to harbor little or no such dark matter. They argue that NGC 1052-DF4, a massive galaxy some 45 million light years away in the southern constellation of Cetus, is being almost completely stripped of this strange matter via gravitational interactions with its nearby galactic neighbor, NGC 1035.

In fact, NASA asserts that the forces driving NGC 1035 to interfere with NGC 1052-DF4 are tearing the latter apart. 

Deep optical imaging of NGC 1052-DF4 has revealed that this galaxy is undergoing tidal disruption, write the authors, caused by its interaction with its neighbor, NGC 1035. Dark matter is less concentrated than stars, and therefore during interactions is preferentially stripped from satellites galaxies, they report.

How does such stripping actually work?

Like the friction of chalk on a blackboard, Mireia Montes, a postdoctoral fellow at the University of New South Wales in Australia and the paper’s lead author, told me. As you write with the chalk, the chalk’s particles are deposited in the direction of your script, she says. 

By rote, as the galaxy continues its interaction with its massive galactic neighbor, the stripped chalk particles would get deposited in the direction of the orbit of the galaxy, says Montes. In this case, what we can see that NGC 1052-DF4’s stars are actually beginning to be stripped from their host galaxy, she says.

Such research provides case studies in how and why large galaxies actually form. Dark matter helps to form galaxies as it provides sort of the gravitational well where ordinary matter can sit and cool down and form stars, says Montes. 

It also acts as a protective shield.  Without this dark matter shield, says Montes, the galaxy would be very unstable and prone to gravitational influence from external forces. Thus, she says, such galaxies wouldn’t survive in an environment where

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Earth is 2,000 light-years closer to supermassive black hole at the center of our galaxy than we thought | World

More than a century ago, Albert Einstein developed his famous theory of relativity. The idea that space and time are linked together means that time travel might be possible … one day, once physicists figure out how it works.

However, travelers and archeologists have known for centuries that the opportunity to step back in time already exists. Yes, really. By visiting archeological sites around the world, you can see how the city of Pompeii worked right before it was covered in volcanic ash, the lost Inca citadel of Machu Picchu, incredible cave drawings in Brazil and Spain, and even the wealthy trading hub of Petra—no flux capacitor required. Even just learning about archeological findings from home, like the Rosetta Stone and its captivating code or a 44,000-year-old pictorial story from Sulawesi, Indonesia, offers a deeper appreciation for collective ancestors and a humbling reminder of our place in the universe.

When it comes to archeological discoveries, you’ve got a seemingly infinite array of options to read and learn about. So which ones have made the biggest impact on scientists’ understanding of humankind? To find out, Stacker took a look at 50 of the greatest archeological findings of all time, based on reports in news outlets (like National Geographic, Smithsonian Magazine, BBC News, and The Guardian), UNESCO World Heritage site listings, articles from archeology magazines, and other publications. The list includes important discoveries from around the world, ranging from the Americas to Asia, and even Antarctica.

While we’re all stuck at home, there’s no better way to transport yourself to a different time and place than by learning about fascinating archeological sites and discoveries across the globe. Click through to see 50 of the greatest archeological discoveries made throughout history—and don’t be surprised if they inspire future travel plans, once it’s safe to explore the world again.

You may also like: Oldest cities in America

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Earth is closer to supermassive black hole at center of our galaxy than we thought

This map has suggested that the center of the Milky Way, and the black hole which sits there, is located 25,800 light-years from Earth. This is closer than the official value of 27,700 light-years adopted by the International Astronomical Union in 1985, the release said.

New type of black hole detected in massive collision that sent gravitational waves with a 'bang'

What’s more, according to the map, our solar system is traveling at 227 kilometers per second as it orbits around the galactic center — this is faster than the official value of 220 kilometers per second, the release added.

These updated values are a result of more than 15 years of observations by the Japanese radio astronomy project VERA, according to an announcement released Thursday from the National Observatory of Japan. VERA is short for VLBI Exploration of Radio Astrometry and refers to the mission’s array of telescopes, which use Very Long Baseline Interferometry to explore the three-dimensional structure of the Milky Way.

Because the Earth is located inside the Milky Way, it’s difficult to step back and see what the galaxy looks like. To get around this, the project used astrometry, the accurate measurement of the position and motion of objects, to understand the overall structure of the Milky Way and Earth’s place in it.

Nobel Prize in Physics awarded for black hole discoveries that revealed the 'darkest secrets of the universe'
The black hole is known as Sagittarius A* or Sgr A* and is 4.2 million times more massive than our sun. The supermassive hole and its enormous gravitational field governs the orbits of stars at the center of the Milky Way. Reinhard Genzel and Andrea Ghez earned the 2020 Nobel prize for physics for its discovery. There are several types of black holes, and scientists believe the supermassive ones may be connected to the formation of galaxies, as they often exist at the center of the massive star systems — but it’s still not clear exactly how, or which form first.

More precise approach

In August, VERA published its first catalog, containing data for 99 celestial objects. Based on this catalog and recent observations by other groups, astronomers constructed a position and velocity map. From this map, the scientists were able to calculate the center of the galaxy, the point that everything revolves around.

Star merger created rare Blue Ring Nebula

VERA combines data from four radio telescopes across Japan. The observatory said that, when combined, the telescopes were able to achieve a resolution that in theory would allow the astronomers to spot a United States penny placed on the surface of the Moon.

To be clear, the changes don’t mean Earth is plunging toward the black hole, the observatory said. Rather, the map more accurately identifies where the solar system has been all along.

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Galaxy encounter violently disturbed Milky Way, study finds

Galaxy encounter violently disturbed Milky Way, study finds
Magellanic clouds over Bromo Semeru Tengger National Park, Java, Indonesia. Credit: Gilbert Vancell- gvancell.com

The spiral-shaped disk of stars and planets is being pulled, twisted and deformed with extreme violence by the gravitational force of a smaller galaxy—the Large Magellanic Cloud (LMC).


Scientists believe the LMC crossed the Milky Way’s boundary around 700 million years ago—recent by cosmological standards—and due to its large dark matter content it strongly upset our galaxy’s fabric and motion as it fell in.

The effects are still being witnessed today and should force a revision of how our galaxy evolved, astronomers say.

The LMC, now a satellite galaxy of the Milky Way, is visible as a faint cloud in the southern hemisphere’s night skies—as observed by its namesake, the 16th century Portuguese explorer Ferdinand Magellan.

Previous research has revealed that the LMC, like the Milky Way, is surrounded by a halo of dark matter—elusive particles which surround galaxies and do not absorb or emit light but have dramatic gravitational effects on the movement of stars and gas in the universe.

Using a sophisticated statistical model that calculated the speed of the Milky Way’s most distant stars, the University of Edinburgh team discovered how the LMC warped our galaxy’s motion. The study, published in Nature Astronomy, was funded by UK Science and Technology Facilities Council (STFC).

The researchers found that the enormous attraction of the LMC’s dark matter halo is pulling and twisting the Milky Way disk at 32 km/s or 115,200 kilometers per hour towards the constellation Pegasus.

To their surprise they also found that the Milky Way was not moving towards the LMC’s current location, as previously thought, but towards a point in its past trajectory.

They believe this is because the LMC, powered by its massive gravitational force, is moving away from the Milky Way at the even faster speed of 370 km/s, around 1.3 million kilometers per hour.

Astronomers say it is as if the Milky Way is trying hard to hit a fast moving target, but not aiming very well.

This discovery will help scientists develop new modeling techniques that capture the strong dynamic interplay between the two galaxies.

Astronomers now intend to find out the direction from which the LMC first fell in to the Milky Way and the exact time it happened. This will reveal the amount and distribution of dark matter in the Milky Way and the LMC with unprecedented detail.

Dr. Michael Petersen, lead author and Postdoctoral Research Associate, School of Physics and Astronomy, said, “Our findings beg for a new generation of Milky Way models, to describe the evolution of our galaxy.

“We were able to show that stars at incredibly large distances, up to 300,000 light-years away, retain a memory of the Milky Way structure before the LMC fell in, and form a backdrop against which we measured the stellar disk flying through space, pulled by the gravitational force of the LMC.”

Professor Jorge Peñarrubia, Personal Chair of Gravitational Dynamics, School of Physics and

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Astronomers spot Earth-sized “rogue planet” in our galaxy, without a star

The rogue planet is not bound by gravity to any star (University of Warsaw)
The rogue planet is not bound by gravity to any star. (University of Warsaw)

There might be billions of “rogue planets” hurtling through our galaxy on their own, orbiting no parent star, researchers have said. 

Polish researchers spotted a brief brightening of a star, caused, they believe, by a Mars-sized planet wandering in front of another star. 

The planet is thought to be a “rogue”, or not bound by gravity to a star, and slightly smaller than Earth. 

Our galaxy could be full of such planets, according to the Ogle team from the Astronomical Observatory of the University of Warsaw. 

Read more: Mysterious ‘rogue planet’ could be even weirder than we thought

Researcher Dr Przemek Mroz of the California Institute of Technology told Live Science: “The odds of detecting such a low-mass object are extremely low.”

“Either we were very lucky, or such objects are very common in the Milky Way. They may be as common as stars.”

The researchers spotted the star due to a phenomenon known as “microlensing”, where a massive object (like a planet) bends the light from a star behind it, due to Einstein’s theory of general relativity.

Mroz said: “If a massive object (a star or a planet) passes between an Earth-based observer and a distant source star, its gravity may deflect and focus light from the source. The observer will measure a short brightening of the source star.”

“Chances of observing microlensing are extremely slim because three objects – source, lens, and observer – must be nearly perfectly aligned.

“If we observed only one source star, we would have to wait almost a million years to see the source being microlensed.”

Read more: There might once have been life on the moon

The researchers believe the event was caused by a planet smaller than Earth, and possibly around the size of Mars. 

The new event, called OGLE-2016-BLG-1928, had a timescale of just 42 minutes.

Dr Radoslaw Poleski from the Astronomical Observatory of the University of Warsaw said: “When we first spotted this event, it was clear that it must have been caused by an extremely tiny object.

“Indeed, models of the event indicate that the lens must have been less massive than Earth – it was probably a Mars-mass object.” 

Read more: Exoplanet twice the size of Earth ‘could be habitable’

New surveys hunting for gravitational microlensing events are monitoring hundreds of millions of stars in the Milky Way centre, where the chances of microlensing are highest. 

The Ogle survey – led by Warsaw University astronomers – is one of the largest and longest sky surveys. It started operations over 28 years ago. 

Currently, Ogle astronomers are using a 1.3-meter Warsaw Telescope located at Las Campanas Observatory, Chile. 

Watch: The future of America’s space race

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ESA Reveals ‘Otherworldly’ Photo Of A Peculiar Galaxy 271 Million Light-Years Away

KEY POINTS

  • The Hubble Space Telescope captured an image of galaxy NGC 34
  • NGC 34 is a peculiar galaxy located in the constellation Cetus
  • The galaxy is a product of two massive spiral galaxies colliding and merging millions of years ago

The NASA/ESA Hubble Space Telescope has captured a photo of a unique galaxy located approximately 271 million light-years away from Earth.

The galaxy, called NGC 34, lies in the constellation Cetus (The Sea Monster) and has an appearance that is continuously changing due to past events. The object, which is the result of two massive spiral galaxies colliding together, is also known as NGC 17, LEDA 781 or Mrk 938.

A tweet posted Monday by the European Space Agency (ESA) Twitter account showed the beautiful, glowing body of NGC 34 that outshines all other objects surrounding it. The otherworldly image captured by the Hubble reveals the galaxy’s translucent outer region that is covered with stars and wispy tendrils, making it look almost like it came straight out of a fairytale.

With a galaxy as peculiar as NGC 34, it is bound to have an interesting past as well.

“If we were able to reverse time by a few million years, we would see two beautiful spiral galaxies on a direct collision course. When these galaxies collided into one another, their intricate patterns and spiral arms were permanently disturbed,” Hubble astronomers said in a statement on the space telescope’s website.

“This image shows the galaxy’s bright center, a result of this merging event that has created a burst of new star formation and lit up the surrounding gas,” the astronomers continued. “As the galaxies continue to intertwine and become one, NGC 34’s shape will become more like that of a peculiar galaxy, devoid of any distinct shape.”

In the vastness of space, it is rare for two galaxies to collide with each other. But it can still occur in mega-clusters containing thousands of galaxies held together by gravity in one large region of space, the astronomers said.

NGC 34 was discovered in 1886 by astronomer Frank Muller. Later that year, it was once more observed by astronomer Lewis Swift. The galaxy has a diameter of about 165,000 light-years, Sci News reported.

The Hubble Space Telescope is a large, space-based observatory designed to observe the universe and the events happening within it. The telescope has made countless observations, including watching a comet collide with Jupiter and discovering moons around Pluto.

NASA also recently shared a stunning image taken by the Hubble. On Monday, the space agency posted a photo of interacting galaxies NGC 2799 and NGC 2798, showing the former seemingly being pulled into the center of the latter.

NASA said the interactions between the two neighboring galaxies could eventually result in a “merger or unique formation,” possibly similar to NGC 34.

Galaxy HSC J1631+4426 Image: Galaxy HSC J1631+4426, which broke the record for having the lowest oxygen abundance. The image was captured using the Subaru Telescope. Photo: NAOJ/Kojima et al.

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The magnetic fields of the jellyfish galaxy JO206

The magnetic fields of the jellyfish galaxy JO206
The galaxy JO206 and its ordered magnetic field (green lines) along the gas tail. Credit:ESO/GASP collaboration, adapted

An international team of astronomers has gained new insights into the physical conditions prevailing in the gas tail of so-called jellyfish galaxies. They are particularly interested in the parameters that lead to the formation of new stars in the tail outside the galaxy disk. They analyzed, for example, the strength and orientation of the magnetic fields in the galaxy JO206.


Ancla Müller and Professor Ralf-Jürgen Dettmar from Ruhr-Universität Bochum describe their findings together with Professor Christoph Pfrommer and Dr. Martin Sparre from the Leibniz Institute for Astrophysics in Potsdam as well as colleagues from the INAF—Italian national institute of Astrophysics in Padua, Selargius and Bologna in the journal Nature Astronomy from 26 October 2020.

Strong magnetic fields

Jellyfish galaxies are galaxies that fall into the center of a galaxy cluster, so that the motion pushes the interstellar gas in the opposite direction. This results in the formation of a tail, which gives these galaxies their jellyfish-like appearance and hence their name. A team led by Bianca Poggianti, one of the authors of the current paper from the INAF, had shown in earlier studies that stars can form in the gas tails of jellyfish galaxies. The fact that magnetic fields in galaxies can contribute to star formation is well known. However, it has not yet been established whether this is also the case in the rarified gas of jellyfish tails, which are difficult to study due to their low brightness.

The team headed by Ancla Müller has now taken a first step towards resolving this issue. The researchers analyzed the magnetic field structure of the galaxy JO206. They have shown that not only the galaxy disk has a strong magnetic field, but also the gas tail. “Considering the unusually high proportion of polarized radiation, we can conclude that the field is aligned very precisely along the tail,” explains Ancla Müller.

Computer simulations provide a possible explanation

Using computer simulations, the group constructed a scenario that can explain the unusual parameters: “While the jellyfish galaxy flies through the galaxy cluster, its magnetic field wraps around the galaxy like a mantle and is further amplified and smoothed by the high galaxy speed and cooling effects,” explains Christoph Pfrommer. This process could amplify the magnetic field of JO206 and also generate the high proportion of polarized radiation.

On the basis of the simulation, the researchers developed the following theory: JO206 falls at high speed into the center of the galaxy cluster, so that the magnetic fields interact and hot winds from the medium between the galaxies lead to accumulations of plasma. A percentage of the plasma condense on the outer layers of the gas tail, where it mixes with the remaining matter. “This would provide enough material for star formation,” says Ancla Müller. “It should be fascinating to see whether this picture can be confirmed by further measurements on other objects.”

“To verify the hypotheses suggested by

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The Milky Way galaxy has a clumpy halo

The Milky Way galaxy has a clumpy halo
A mini satellite designed and built at the University of Iowa has determined the Milky Way galaxy is surrounded by a heated, clumpy halo of gas that is continually being supplied by birthing or dying stars in our galaxy. Credit: Blue Canyon Technologies

The Milky Way galaxy is in the recycling business.


University of Iowa astronomers have determined our galaxy is surrounded by a clumpy halo of hot gases that is continually being supplied with material ejected by birthing or dying stars. This heated halo, called the circumgalactic medium (CGM), was the incubator for the Milky Way’s formation some 10 billion years ago and could be where basic matter unaccounted for since the birth of the universe may reside.

The findings come from observations made by HaloSat, one of a class of minisatellites designed and built at Iowa—this one primed to look at the X-rays emitted by the CGM. The researchers conclude the CGM has a disk-like geometry, based on the intensity of X-ray emissions coming from it. The HaloSat minisatellite was launched from the International Space Station in May 2018 and is the first minisatellite funded by NASA’s Astrophysics Division.

“Where the Milky Way is forming stars more vigorously, there are more X-ray emissions from the circumgalactic medium,” says Philip Kaaret, professor in the Iowa Department of Physics and Astronomy and corresponding author on the study, published online in the journal Nature Astronomy. “That suggests the circumgalactic medium is related to star formation, and it is likely we are seeing gas that previously fell into the Milky Way, helped make stars, and now is being recycled into the circumgalactic medium.”

Each galaxy has a CGM, and these regions are crucial to understanding not only how galaxies formed and evolved but also how the universe progressed from a kernel of helium and hydrogen to a cosmological expanse teeming with stars, planets, comets, and all other sorts of celestial constituents.

HaloSat was launched into space in 2018 to search for atomic remnants called baryonic matter believed to be missing since the universe’s birth nearly 14 billion years ago. The satellite has been observing the Milky Way’s CGM for evidence the leftover baryonic matter may reside there.

To do that, Kaaret and his team wanted to get a better handle on the CGM’s configuration.

More specifically, the researchers wanted to find out if the CGM is a huge, extended halo that is many times the size of our galaxy—in which case, it could house the total number of atoms to solve the missing baryon question. But if the CGM is mostly comprised of recycled material, it would be a relatively thin, puffy layer of gas and an unlikely host of the missing baryonic matter.

“What we’ve done is definitely show that there’s a high-density part of the CGM that’s bright in X-rays, that makes lots of X-ray emissions,” Kaaret says. “But there still could be a really big, extended halo that is just dim in X-rays. And it might be harder

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