Astronomy

Has the Milky Way collided with another galaxy?

Has the Milky Way collided with another galaxy?


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

Has the Milky Way ever collided with another galaxy? Or will the collision with Andromeda be our first?


According to our current understanding of physical cosmology (as contrasted with cosmologies of various cultural references) the Milky Way must necessarily have had collisions in a process called hierarchical clustering.
How we're certain of this is the following:

  • No matter what exactly happened at the big bang, we know the state of the universe at roughly the age of ~380.000 years, where the universe becomes transparent (more or less instantaneous, but let's omit that discussion). At this moment, matter emits light that teaches us the distribution of matter in the young universe. This is the Cosmic Microwave Background Radiation.
  • In the CMB we see that matter is remarkably homogeneous, apart from very small fluctuations, that help us build the cosmological standard model. This means at the time of the CMB emission, the universe had nearly the same matter density everywhere. Which is the contrary of clustered matter blobs (galaxies) that we see today.


Fig. 1: CMB temperature fluctuations as seen by WMAP.
Those variations can be translated into density fluctuations, given a physical model. To our current understanding the form the seeds of galaxy growth.

  • Now we take those small fluctuations, add dark matter and evolve a model of the universe over time, in large-scale compuational facilities. Then we find that galaxies are a natural outcome of the small CMB fluctuations that become gravitationally unstable. Those unstable blobs of matter amplify the initial fluctuations, until whole pockets of matter collapse into dense, rotating objects.
  • Those objects would be dwarf galaxies, and those collide and merge and thus grow into larger, mature galaxies. This is the process of hierarchical clustering, I was referring to above. This process can be simplified to "small things collapse first", as opposed to "large things collapse first". In the latter case the Milky Way would not have had collisions before.

Summarizing
Yes, our galaxy had collisions before, and they were necessary to grow to it's current size. Scientists are searching for the relics of those collisions in a process called galactic archaeology (the link goes to a personal website, which I find neatly made).


Yes. We can see "stellar streams" surround the Milky Way, long streams of stars from globular clusters and dwarf galaxies that have been disrupted by the galaxy and are now slowly merging with it. There is an upper limit (based on the amount of blue stars in the halo) of about 60 past such mergers.

It does not look like the Milky Way formed from a big merger. Had it done so it would have a much thicker and fuzzier disk (lots of "heating" by having stars in random orbits). The Andromeda collision will turn the galaxies into an elliptical galaxy, which has even less structure.


Rethinking the Formation of the Milky Way

Ten billion years ago, the Milky Way galaxy collided with a satellite galaxy, just as our family of stars began to take shape, new research reveals. Astronomers studied the ages of roughly 100 red giant stars around the Milky Way, using newly-developed techniques.

This new study could help us better understand both formation of the Milky Way, as well as the evolution of galaxies around the Cosmos.

“The Milky Way, like other disk galaxies, underwent violent mergers and accretion of small satellite galaxies in its early history. Owing to Gaia Data Release 2 and spectroscopic surveys, the stellar remnants of such mergers have been identified,” researchers describe in Nature Astronomy.

The Smell of Homemade Stars — Yum!

Sound waves radiating through stars, revealed by asteroseismology, details processes occurring deep within the interior of stars. The chemical composition of the stars was also examined through chemical analysis, provided in the APOGEE survey, providing further evidence for stellar ages.

Researchers found a fraction of stars currently in our galaxy came from this satellite galaxy, Gaia-Enceladus, while others were already in our nascent family of stars.

“Our evidence suggests that when the merger occurred, the Milky Way had already formed a large population of its own stars,” said Fiorenzo Vincenzo of Ohio State University’s Center for Cosmology and Astroparticle Physics.

Looking at data from the stars, a pattern started to emerge — the “homemade” stars present before the merger congregate near the center of our galaxy, while those from Gaia-Enceladus are now found closer to the rim of the Milky Way. The stars from the satellite galaxy were also found to be younger than those which developed in our own galaxy, the study finds.

Galactic Introspection

“A broad and ample road, whose dust is gold, and pavement stars — as starts to thee appear soon in the galaxy, that milky way
Which mightly as a circling zone thou seest powder’d with stars.”
― John Milton, Paradise Lost

Although it may seem counter-intuitive, studies of the Milky Way are hindered by the fact that we live within the galaxy.




This simulation shows the merger of several small galaxies, forming a spiral galaxy similar to the Milky Way. Video credit: NCSA/NASA

“[O]bserving a galaxy from the inside out is not an easy task. Even a comprehensive census of stars in the Milky Way has been beyond our reach, with much of the stellar population consisting of small, faint, hard-to-see red dwarf stars, while many stars are hidden by vast clouds of dust. Creating a three-dimensional map of the Milky Way has also proven difficult, and any details such a map could give us about galactic structures or stellar associations remains beyond our reach,” researchers at the Vera C. Rubin Observatory explain.

The merger event shook things up in the galaxy, affecting the orbits of native stars, making their paths more erratic. The stars themselves even show different chemical compositions than those living in our galaxy prior to the merger.

“The merging event with Gaia-Enceladus is thought to be one of the most important in the Milky Way’s history, shaping how we observe it today,” explains Josefina Montalban from the School of Physics and Astronomy at the University of Birmingham.

Expanding this study to a larger number of stars will allow astronomers to better understand both the formation of Milky Way, and how our family of stars developed long before the Earth first took shape.

The James Webb Space Telescope, scheduled for launch this Autumn, will tell us more about the formation of galaxies as it looks deep in space and far back in time, examining the first galaxies in the Cosmos.

James Maynard

James Maynard is the founder and publisher of The Cosmic Companion. He is a New England native turned desert rat in Tucson, where he lives with his lovely wife, Nicole, and Max the Cat.

Storms on Jupiter Reveal Secrets of Atmosphere

The Volcano Planet LHS 3844b

A Eulogy for the Arecibo Radio Telescope

3 thoughts on &ldquo Rethinking the Formation of the Milky Way &rdquo

Where does the Sun fit into this scenario? It’s about half way out from the galaxy center. Is it original galaxy, or gobbled-up galaxy? Or is it younger than the galactic era you describe?

Good question! Our Sun only formed about 4.5 billion years ago, so it formed long after the merger. Thanks for reading!

Upcoming Guests

June 29 (s4/e26): Alyssa Mills, Graduate intern at JPL, talks about the largest moon in the Solar System, Ganymede.

July 6 (s5/e1): SEASON FIVE PREMERE! New York Times bestselling author Earl Swift, author of Across the Airless Wilds, the first major history of NASA’s lunar buggy.

July 13 (s5/e2):

Stella Kafka, CEO of The American Association of Variable Star Observers, talking about Betelgeuse.

July 20 (s5/e3):

Geoff Notkin, host of Meteorite Men on the Science Channel and president of the National Space Society, talks meteorites.

July 27 (s5/e4):

CHIME member Kaitlyn Shin, MIT grad student, explains fast radio bursts (FRBs)

August 3 (s5/e5):

Teaching science to children with Stephanie Ryan, author of “Let’s Learn Chemistry.”

Subscribe to our Newsletter!

Yes! Sign me up for the Cosmic Companion newsletter!

Appreciation

“Nobody doesn’t love astronomy out there, and you’re in the middle of that, so keep that going.” – Neil deGrasse Tyson

“The show is a great way to keep up with new discoveries in space sciences. One gets to directly hear from scientists in an easy to understand language.”- Dr. Dimitra Atri, NYU Abu Dhabi

“Your site is great, and I think your videos are wonderful.” – Dr. Jack Hughes, Rutgers University


Milky Way: Astronomers discover evidence of 'violent' collision of Milky Way

Link copied

Milky Way: Satellite captures galactic disc 'wobbling'

When you subscribe we will use the information you provide to send you these newsletters. Sometimes they'll include recommendations for other related newsletters or services we offer. Our Privacy Notice explains more about how we use your data, and your rights. You can unsubscribe at any time.

Around 700 million years ago - which is still fresh in astronomical terms - a small galaxy collided with the Milky Way, leading to permanent damage to our galactic home. A small satellite galaxy which hovers around the edge of the Milky Way came colliding into our galaxy, leading to parts of our starry home becoming twisted and distorted.

Related articles

The particles themselves are invisible and made of mystery substance unbeknown to astronomers.

However, they can be analysed by the effect they have on surrounding stars and gasses.

The analysis showed that the halo of dark matter is contorting the disc of the Milky Way.

As a result, part of our galaxy is being pulled to the constellation Pegasus.

Milky Way: Astronomers discover evidence of 'violent' collision of Milky Way (Image: GETTY)

The LMC is a satellite galaxy (Image: GETTY)

The particles themselves are invisible and made of mystery substance unbeknown to astronomers.

However, they can be analysed by the effect they have on surrounding stars and gasses.

The analysis showed that the halo of dark matter is contorting the disc of the Milky Way.

As a result, part of our galaxy is being pulled to the constellation Pegasus.

The LMC and the SMC (Image: Gilbert Vancell- gvancell.com)

Related articles

The strange direction, according to the research published in the journal Nature Astronomy, is due to the LMC moving much faster than the Milky Way.

The LMC is pulling and twisting the Milky Way disk at 32 km/s or 115,200 kilometres per hour towards the constellation Pegasus.

This is down to the LMC, which has a powerful galactic pull due to its denseness, moving at the extremely fast speed of 370 km/s, around 1.3 million kilometres per hour.

Astronomers will now try to determine the direction of which the LMC collided with the Milky Way.

Hubble in numbers (Image: EXPRESS)

Trending

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 Astronomy, said: "This discovery definitely breaks the spell that our galaxy is in some sort of equilibrium state.

"Actually, the recent infall of the LMC is causing violent perturbations onto the Milky Way.

"Understanding these may give us an unparalleled view on the distribution of dark matter in both galaxies."


The Milky Way Is on Course to Collide With Another Galaxy, Causing 'Cosmic Fireworks' Like Nothing We've Ever Seen (Video)

The Milky Way Galaxy — home to planet Earth — is on a collision course with another interstellar body, a spiral of stars known as the Large Magellanic Cloud (LMC). When the two finally meet it will not only create a massive black hole, but it may also fling our solar system thousands of lightyears away.

That might sound scary, but don’t worry too much, as this isn’t expected to happen for another few billion years.

In a new report published in Monthly Notices of the Royal Astronomical Society, researchers from Durham University theorize that our galaxy and its closest neighbor will run into one another in one billion to four billion years. While the event could potentially be harmful to humans who may still be on Earth, it will also put on a light show we 21st-century kids couldn’t even dream of.

“The discovery made me very excited!” the study’s lead author Marius Cautun, Ph.D., told Inverse. “Initially, both my collaborators and I were surprised and, because we didn’t expect it, a bit skeptical. This happens many times with new discoveries.”

So what exactly will go down in a few billion years? According to QZ.com, when the Milky Way absorbs the LMC, the black hole that sits in the center of our galaxy could inflate to about eight times its normal size. That will make it easy to ingest any stars or matter near it. That, QZ.com explained, may even turn the black hole into what is known as a quasar, which would make it one of the brightest objects in the entire universe.

As Carlos Frenk, the study’s co-author, wrote, it will be 𠇊 spectacular display of cosmic fireworks as the newly awakened supermassive black hole at the center of our galaxy reacts by emitting jets of extremely bright energetic radiation.”

Our solar system will likely be safe, but there’s still a chance we too will be ejected.

“The collision will not affect directly the Solar System, however, it will trigger a secondary chain of events that can pose a danger to life,” Cautun added. 𠇊ny such change is very dangerous for life, since even small variations in the distance between the Earth and the Sun can move our planet outside the Goldilocks zone and make it either too hot or too cold for life.”

Maybe Richard Branson and Elon Musk should team up to make interstellar travel happen sooner rather than later. You know, just to be safe.


Strange stars

Astronomers know the Milky Way has devoured several galaxies already. Some two dozen ribbons of stars streaming around the galaxy’s disk betray its predatory appetite, as do other oddly behaving, oddly composed stars. As further evidence, an enigmatic cluster of stars called Omega Centauri, which now sparkles in the southern constellation Centaurus, is thought to be the core of a mostly digested galaxy.

But recently, the European Space Agency’s Gaia spacecraft, which is taking an exquisitely detailed look at the positions and movement of more than a billion nearby stars, shook a new clue loose from the heavens. When Helmi and her team looked at the most recent Gaia catalogue, released earlier this year, they noticed a population of stars moving backward relative to almost everything else trekking around the Milky Way’s core. If those stars had been born in this galaxy, they would be marching around the core in the same direction as the rest of us.

Then, Helmi and her colleagues noticed something else.

“When we looked at their chemical composition, we saw that the stars defined a separate sequence in ‘chemical space,’” Helmi says. “Such a sequence can only be found if the stars formed elsewhere in a smaller galaxy.”

Those chemically distinct stars are distributed mostly in the Milky Way’s halo, or the region surrounding the thick stellar disk that weaves its way through a dark sky.

The team’s observations matched simulations of a collision with a smaller galaxy, and based on the ages of those strangely constructed stars traveling in the wrong direction, the team calculated that the smash-up would have occurred about 10 billion years ago, and that the dwarf galaxy would have been comparable in size to the Large Magellanic Cloud, a present-day satellite galaxy.

Helmi and her colleagues named the dwarf galaxy Gaia-Enceladus, after Gaia, the Greek mother of all life, and Enceladus, the son she had with Uranus, the sky god.


The Milky Way Ate Another Galaxy 10 Billion Years Ago—And We Now Know More About This Cosmic Cannibalism Event

Ten billion years ago, the Milky Way gobbled up another galaxy, creating the cosmic structure our solar system sits in today. By analyzing the age distribution of stars in the Milky Way's inner halo, scientists have now been able to create a better picture of our galaxy's formation.

They found that many of the stars in the inner halo are up to 10 billion years old, providing more evidence of the timing of the merger&mdashand helping identify the Milky Way's original stars that were there at its onset, 13.5 billion years ago.

Galaxies are not in fixed positions in space. They move around over time, occasionally smashing into one another.

Evidence of a massive merger between the Milky Way and the Gaia Enceladus galaxy came in 2018 when scientists used data from the European Space Agency's Gaia satellite to show a vast number of stars appeared to be out of place. In a letter published by Nature, the team said the inner halo of the Milky Way is "dominated by debris" from another galaxy. This galaxy was found to be about a quarter of the size of the Milky Way.

However, when this huge collision took place has been debated.

In a study published in Nature Astronomy on Monday, scientists led by Carme Gallart, from Spain's Institute of Astrophysics of the Canary Islands, looked at the stars in the Milky Way's inner halo and created cosmological simulations to find the age limit for when the merger took place.

Their findings showed that most of the stars in the inner halo are up to 10 billion years old&mdashsuggesting this is the point when the merger took place. By being able to put a constraint on the timing of the merger, the team was also able to identify the Milky Way's original stars.

Concluding, they say the simulations provide a "clear picture of the formation" of the Milky Way: "In this picture, a primitive Milky Way had been forming stars over a period of some [three billion years] when a smaller galaxy, which had been forming stars on a similar timescale but was less chemically enriched owing to its lower mass, was accreted into it."

They said heat from the merger helped create the halo-like configuration we see today, and that a large supply of gas "ensured the maintenance of a disk-like configuration, with the thick disk continuing to form stars at a substantial rate."

Gallart told Newsweek: "Finding the date of the merger helps to understand what are its effects in the Milky Way. For example, in our study we see that, after the merger, the rate at which stars form in the Milky Way disk go up, and thus we can infer that this merger contributed to star formation in the disk of the Milky Way."

This is not the only time the Milky Way has merged with other galaxies. It is thought that throughout its history it has consumed many other, smaller galaxies.

Effects of mergers are not really noticeable on a small scale, Gallart said. "The distance between stars in a galaxy are so huge. that the two galaxies intermix, change their global shape, more star formation may happen in one and maybe the other&mdashthe small one&mdashstops forming stars.

"But the individual stars in each galaxy don't collide, don't really notice the force of the event in a way that affect their individual evolution, or the evolution of the planetary systems that may be attached to them."

At the moment, the Milky Way is colliding with the Canis Major Dwarf galaxy. Our solar system is believed to have entered the Milky Way during a merger with the Sagittarius dwarf galaxy.

Eventually, the Milky Way will merge with our largest, closest neighbor, Andromeda. When this happens, around 4.5 billion years from now, the Milky Way as we know it will cease to exist.


The Milky Way went cannibal and absorbed another galaxy when it was young

Scientists from the Instituto de Astrofísica de Canarias (IAC) have created a new cosmic picture of the Milky Way galaxy which shows its origins, before it gobbled up another smaller galaxy called Gaia-Enceladus after the two galaxies collided.

Although scientists knew that the galaxies had merged before now, the timeline of the collision and its aftermath was debated. Thanks to recent accurate stellar age data gathered by the European Space Agency&rsquos Gaia spacecraft mission, the team was able to create a color magnitude diagram showing the age distribution of stars in the current disk and inner halo of the Milky Way, allowing them to identify when the merger took place.

&ldquoTogether with state-of-the-art cosmological simulations of galaxy formation, these robust ages allow us to order the early sequence of events that shaped our Galaxy,&rdquo the study published in Nature Astronomy explains.

The team tracked how different stars moved and looked at the difference in their chemical make-ups. They then identified two different groups of Milky Way stars, a red group, with a higher concentration of metals, and a blue group, with lower metal concentration, both groups contained stars that were the same age. They determined that the blue group must have belonged to Gaia-Enceladus.

Both galaxies appeared about 13 billion years ago and collided 3 billion years later, in a process that took millions of years and saw Gaia-Enceladus be absorbed into the Milky Way. The process caused the stars in the young Milky Way to heat up and form a stellar halo. Gas fell towards the center, creating a disk shape, which continued to form stars. Around 6 or 8 billion years ago, the gas settled into a thin disk that continues to form stars.

&ldquoWe can measure these effects much more accurately in the Milky Way than in external galaxies, and this will provide many new insights on the physical mechanisms that play a role in the evolution of galaxies,&rdquosaid lead researcher Carme Gallart.


Milky Way Collided with Dark-Matter Dominated Galaxy Less Than Billion Years Ago

According to new research led by Rochester Institute of Technology (RIT), the collision of the recently-discovered dwarf galaxy Antlia 2 with our Milky Way Galaxy hundreds of millions of years ago is responsible for ripples in the Milky Way’s outer gas disk.

The Large Magellanic Cloud, the Milky Way Galaxy and Antlia 2 (from left to right). Image credit: V. Belokurov / Marcus and Gail Davies / Robert Gendler.

Antlia 2 was discovered in 2018 in data from the second data release of ESA’s Gaia mission.

The dwarf galaxy is located in the constellation Antlia, approximately 130,000 light-years from Earth.

It is as big as the Large Magellanic Cloud, and a third the size of the Milky Way itself.

Antlia 2’s current location closely matches the location of a dark-matter dominated dwarf galaxy that astronomers predicted in 2009 through a dynamical analysis.

Using the Gaia data, they calculated its past trajectory and found that Antlia 2 would have crashed into the Milky Way and produced the large ripples that we see in its outer gas disk.

“The discovery could help develop methods to hunt for dark galaxies and ultimately solve the long-standing puzzle of what dark matter is,” said RIT astrophysicist Sukanya Chakrabarti, lead author of the study.

“We don’t understand what the nature of the dark matter particle is, but if you believe you know how much dark matter there is, then what’s left undetermined is the variation of density with radius.”

“If Antlia 2 is the dwarf galaxy we predicted, you know what its orbit had to be. You know it had to come close to the galactic disk. That sets stringent constraints, therefore, on not just on the mass, but also its density profile. That means that ultimately you could use Antlia 2 as a unique laboratory to learn about the nature of dark matter.”

Dr. Chakrabarti and her colleagues also explored other potential causes for the ripples in the Milky Way’s outer disk, but ruled out the other candidates.

The Sagittarius dwarf galaxy’s tidal strength was insufficient and the Large and Small Magellanic Clouds are too distant.

The evidence points to Antlia 2 as the most likely cause.

“Upcoming additional data releases from Gaia will provide further clarity,” Dr. Chakrabarti said.

“We made a hand-on-the-cutting-board kind of prediction of what to expect for the motion of the stars in the Antlia 2 dwarf galaxy in future Gaia data releases.”

Sukanya Chakrabarti et al. 2019. Antlia2’s role in driving the ripples in the outer gas disk of the Galaxy. ApJL, in press arXiv: 1906.04203


The Disk of the Milky Way is Warped Because it Already Collided With Another Galaxy

For decades, astronomers have been trying to understand why the Milky Way galaxy is warped the way it is. In recent years, astronomers have theorized that it could be our neighbors, the Magellanic Clouds, that are responsible for this phenomenon. According to this theory, these dwarf galaxies pull on the Milky Way’s dark matter, causing oscillations that pull on our galaxy’s supply of hydrogen gas.

However, according to new data from the European Space Agency’s (ESA) star-mapping Gaia Observatory, it is possible that this warp is the result of an ongoing collision with a smaller galaxy. These findings confirm that the warp in our galaxy is not static, but subject to change over time (aka. precession), and that this process is happening faster than anyone would have thought!

Astronomers have known since the late 1950s that disk of the Milky Way, where most of its stars reside – is curved upwards on one side and downwards on the other. However, the reasons for this have remained unclear, with theories ranging from the influence of the intergalactic magnetic field, the gravitational effects of an irregularly-shaped dark matter halo.

To shed some light on this, a team of astronomers from the Turin Astrophysical Observatory in Italy and the Max Planck Institute for Astronomy in Germany consulted astrometric measurements from the second Gaia data release (DR2). This latest package (which was released on April 25th, 2018) contains updated information on the position, motion, and distances of 1.692 billion stars.

Using this data, the team was able to examine the behavior of stars located in the outer disk, from which they confirmed that the galaxy’s warp is not static but changes its orientation over time. This change in orientation, known as precession, is similar the same way that a planet experiences a “wobble” because of the way they rotate on their axis.

In addition, they also found that the precession of this warp is happening at a much faster rate than expected – far faster than what an intergalactic magnetic field or a dark matter halo would be capable of. The team concluded from this that something more powerful has to be influencing the shape of our galaxy, like a collision with another galaxy.

The structure of the Milky Way, showing the warped sections of the disk. Credit and Copyright: Stefan Payne-Wardenaar Inset: NASA/JPL-Caltech Layout: ESA

The study that describes their findings, titled “Evidence of a dynamically evolving Galactic warp“, recently appeared in the journal Nature Astronomy. As Eloisa Poggio of the Turin Astrophysical Observatory, who is the lead author of the study, explained in an ESA press release:

“We measured the speed of the warp by comparing the data with our models. Based on the obtained velocity, the warp would complete one rotation around the center of the Milky Way in 600 to 700 million years. That’s much faster than what we expected based on predictions from other models, such as those looking at the effects of the non-spherical halo.”

However, the speed of the warp’s precession is slower than the speed at which stars in the Milky Way disk are orbiting around the galactic center. For instance, our Sun orbits the center of the Milky Way at an average velocity of 230 km/s (828,000 km/h 514,495 mph) and takes about 220 million years to complete a single orbit.

At present, it is unknown which galaxy might be causing the ripple or when the collision started. However, the team suspects that it could be the Sagittarius Dwarf Galaxy, an elliptically-shaped collection of about 10,000 stars that orbits the Milky Way from pole to pole, and at a distance of about 50,000 light-years.

The Sagittarius dwarf galaxy in Gaia’s all-sky view. Credit: ESA/Gaia/DPAC

Astronomers believe that this dwarf galaxy is gradually being absorbed by the Milky Way, a process that is believed to have caused it to crash through the Milky Way’s disk several times in the past. If the sound of this is making anyone feel nervous, they should take comfort in the fact that these changes are happening on a galactic scale and very far away – hence, they will have no noticeable effects on life on Earth.

This is research serves as an example of the unprecedented ability of the Gaia Observatory to map our galaxy in 3D, as well as the kinds of research that this makes. As Ronald Drimmel, a research astronomer at the Turin Astrophysical Observatory and a co-author of the paper, described it:

“It’s like having a car and trying to measure the velocity and direction of travel of this car over a very short period of time and then, based on those values, trying to model the past and future trajectory of the car. If we make such measurements for many cars, we could model the flow of traffic. Similarly, by measuring the apparent motions of millions of stars across the sky we can model large scale processes such as the motion of the warp.”

These findings are similar to other research findings that were made thanks to Gaia. In 2018, a team of astronomers used the first 22 months of mission data to determine that the Milky Way and other galaxies underwent collisions and mergers in the distant past, the evidence of which is still visible today in the motions of large groups of stars.

“With Gaia, for the first time, we have a large amount of data on a vast amount stars, the motion of which is measured so precisely that we can try to understand the large scale motions of the galaxy and model its formation history,” said Jos de Bruijne, the Gaia deputy project scientist. “This is something unique. This really is the Gaia revolution.”

The mission is currently in its sixth year and (barring extensions) will continue to gather astrometric data until 2022. In the meantime, astronomers are eagerly awaiting the next two releases of Gaia data (DR3 and DR4), which are planned for later in 2020 and in the second half of 2021. Given what we’ve already learned from this mission, one can only speculate as to the other mysteries it will help unravel!


Milky Way could hit another galaxy in 2 billion years, sending solar system flying

The Milky Way Galaxy — home to planet Earth — is on a collision course with another interstellar body, a spiral of stars known as the Large Magellanic Cloud (LMC).

The Whirlpool Galaxy and companion galaxy as seen by the Hubble Space Telescope. This represents a merger between two galaxies similar in mass to the Milky Way and the Large Magellanic Cloud. (Photo: NASA, ESA, S. Beckwith (STScI), and The Hubble Heritage Team (STScI/AURA))

Talk about your fender bender.

Although it's not something we have to worry about any time soon, our Milky Way galaxy could collide with a nearby galaxy (the Large Magellenic Cloud) in a "spectacular" cosmic collision in about 2 billion years, a new study suggests.

Future earthlings may find this of interest, since the collision might knock our solar system "out of the Milky Way and into intergalactic space," said study lead author Marius Cautun of Durham University in the U.K.

Fortunately for our descendants – or whatever species still lives here at that time –researchers say it’s unlikely that this event will put life on Earth at risk, according to Quartz.

Study co-author Carlos Frenk, also of Durham, said that "barring any disasters, like a major disturbance to the Solar System, our descendants, if any, are in for a treat: a spectacular display of cosmic fireworks as the newly awakened supermassive black hole at the center of our galaxy reacts by emitting jets of extremely bright energetic radiation."

Rooftop bars might be packed that night.

In any event, "the destruction of the Large Magellanic Cloud, as it is devoured by the Milky Way, will wreak havoc with our galaxy," according to Cautun. It will turn the Milky Way into "an active galactic nucleus or quasar," he said.

The event may seem far away for most people, but not for astronomers. "While two billion years is an extremely long time compared to a human lifetime, it is a very short time on cosmic timescales," Cautun said in a statement.

The Large Magellanic Cloud is the brightest satellite galaxy of the Milky Way and only entered our "neighborhood" about 1.5 billion years ago, according to the study. It's about 163,000 light years from the Milky Way.

The collision could occur much earlier than the predicted impact between the Milky Way and another neighboring galaxy, Andromeda, which scientists say will hit our galaxy in about 8 billion years.

The study was published Jan. 4 in the peer-reviewed journal Monthly Notices of the Royal Astronomical Society.


Watch the video: Το Τραγούδι του Γαλαξία Galaxy Song cover. Astronio Special #4 (May 2022).