Milky Way has merged with numerous galaxies

Studying globular clusters gives scientists insight into galaxy’s history.

Since its formation billions of years ago, the Milky Way has merged with 12 galaxies of similar size and three dwarf galaxies, according to a study by astronomers at the University of Heidelberg in Germany.

The researchers arrived at this conclusion by studying globular clusters, dense clusters comprised of hundreds of thousands of stars, in the Milky Way’s halo.

A galaxy’s halo is spherical region of stars, gas, and dust extending beyond its main structure. It typically contains numerous globular clusters and older, metal-poor stars.

To learn more about the Milky Way’s long history, the research team studied 96 globular clusters orbiting the center of the galaxy, measuring the ages and levels of heavy elements in their stars.

Galaxies with large numbers of stars containing heavy elements are typically older than those with mostly metal-poor stars, as the former have had more time to merge with and devour other galaxies in their neighborhoods.

The Milky Way’s globular clusters were found to contain an abundance of metal-rich stars, indicating the galaxy has been merging with other galaxies for as long as 12 billion years.

In addition to having collided and merged with many galaxies of roughly its size, the Milky Way has also devoured at least two dwarf galaxies, the research team concluded, based on their discovery of 25 globular clusters containing metal-poor stars.

Currently, the galaxy is in the process of merging with the Sagittarius dwarf galaxy, one of nine satellite galaxies in orbit around the Milky Way. Completion of the merger will occur over approximately 100 million years, during which the Milky Way’s powerful gravitational pull will tear the much smaller Sagittarius dwarf galaxy apart.

Suspected to harbor some dark matter, the Sagittarius dwarf galaxy survived several previous collisions with our galaxy, the researchers found.

Remnants of galaxies devoured by the Milky Way exist in the form of stellar streams, which the researchers observed with the 570-megapixel Dark Energy Camera at the Cerro Tololo Inter-American Observatory in Chile.

Based on these stellar streams’ positions and trajectories, the researchers were able to determine they originated in other galaxies that merged with the Milky Way.

A paper on these findings has been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.

Most known exoplanets are water worlds, study reports

Scientists have found that most of the exoplanets on record hold quite a bit of water.

A group of international astronomers have found that many exoplanets two to four times the size of Earth have water on their surface, according to new research presented at the Goldschmidt conference in Boston.

Astronomers first uncovered exoplanets orbiting distant starts in 1992. Since that time, scientists have spent years attempting to uncover their composition. The new research — which comes from data collected by the  Kepler Space Telescope and the Gaia mission — shows that many known worlds could be up to 50 percent water.

Such exoplanets are exciting because they could well change the way researchers search for life in the universe.

“It was a huge surprise to realize that there must be so many water-worlds,” said lead researcher Li Zeng, a researcher at Harvard University, according to Science Daily.

Researchers found that almost all of the 4000 confirmed exoplanets on record fall into one of two categories. They either have an average planetary radius that is 1.5 times Earth’s, or they have one that is 2.5 times Earth’s. That distinction helped the team piece together the internal structure of the distant bodies.

Models created from the data showed that exoplanets with a radius 1.5 times Earth’s are generally rocky, while the ones that have radii 2.5 Earth’s are likely water worlds.

Though water is not as common on such places as it is on Earth, and while the surface temperatures are much too hot to support conventional organisms, the exoplanets could still offer new insight into the universe. Researchers plan to continue exploring them and potentially gain more insight into their mechanisms in the future.

That is because the presence of water, regardless of other conditions, always means there is a chance for life. Even so, the team also states that just because a world has water does not mean there is life. More research has to be done on individual world’s before such claims could be made.

“One has to realize that, although water appears to be precious and rarer on Earth and other inner solar system terrestrial planets, it is in fact one of the most abundant substance in the universe, since oxygen is the third most abundant element after hydrogen and helium,” added Zeng, according to Discover Magazine.

Astronomers report latest detection of radio bursts coming from space

The recent detection reflects lower frequencies than what astronomers have reported in the past.

Fast Radio Bursts (FRBs) are some of the most explosive events in the Universe. They can generate as much energy as 500 million Suns in milliseconds, and there could be as many as one happening every second, writes Fiona Macdonald for Science Alert. Now, astronomers report detection of another FRB hitting Earth from an unknown source. This particular radio burst falls within the lower end of the spectrum, within the 50 megahertz frequency range, nearly 200 MHz lower than any other signal scientists have detected before. FRBs are incredibly mysterious, astronomers don’t yet know what’s causing them.

Although one of the signals detected has sent out multiple FRBs from the same location—allowing scientists to pinpoint where in the Universes it’s coming from—they still aren’t certain what caused it. Most signals are only detected once, making it difficult for astronomers to determine the source. The recent FRB was detected on July 25, 2018 and reported in The Astronomer’s Telegram. It has been named FRB 180725A, and was caught by an array of radio telescopes in British Columbia, Canada. The Astronomer’s Telegram is a bulletin board of observations posted by accredited researchers, however these observations haven’t been peer reviewed and verified by independent teams. Still, the results make it the first detection of a FRB under 700 MHz. “These events have occurred during both the day and night, and their arrival times are not correlated with known on-site activities or other known sources,” stipulates Patrick Boyle, project manager for the Canadian Hydrogen Intensity Mapping Experiment (CHIME).

Hypotheses abound for the source of FRBs, including black holes, imploding pulsars, and magnetars emitting giant flares to name a few. According to a Harvard physicist, it’s not impossible that FRBs could be engines firing on alien spaceships. While scientists are working to discover the source, they have learned that FRBs cover a spread of frequencies, they seem to be coming from billions of light-years away, and the source of the bursts has to be very energetic. Solving this mystery could help further understanding of the origin of the Universe.

UV light shows which exoplanets may harbor life

A new study shows that UV light is key in providing the building blocks needed for life.

Researchers from the University of Cambridge and the Medical Research Council Laboratory of Molecular Biology have identified a group of exoplanets with the same chemical conditions that may have once allowed life to exist on Earth, according to a new study published in the journal Science Advances.

In the research, the team found that ultraviolet (UV) light sparks a series of chemical reactions that produce the essential building blocks needed to create life.

Using that idea, they then identified multiple planets that both sit inside their star’s habitable zone and get enough UV light from their host star to spark such reactions.

It is those distant worlds where life is most likely be found.

The team began the study by theorizing that cyanide helped life exist on early Earth. They argued that carbon from meteorites slammed into our planet millions of years ago and interacted with nitrogen to create hydrogen cyanide.

The cyanide then rained to the surface, where it reacted with the sun’s UV light and generated the first building blocks for RNA.

After using UV lamps to recreate such reactions in the lab, the team managed to build many of life’s essential elements, including lipids, amino acids, and nucleotides.

From there, researchers ran a series of experiments to see how quickly the mix of UV light, water, and hydrogen cyanide or sulphite ions can create those key building blocks. They then repeated the process without light.

That showed, while stars around the same temperature as our sun are able to create the right amount of light for life’s building blocks, cool stars cannot.

As a result, the team believes the only planets worth searching for life at are ones in the so-called abiogenesis zone — a region where planets get both liquid water and enough light to activate basic chemistry.

“The thing that you know best about any exoplanet system is the star,” lead author Paul Rimmer, an astrochemist at the University of Cambridge, told Space.com. “So, that seemed like a natural thing to start with.”

While only a few known exoplanets sit in that zone, the team hopes future technology will be able to track down more hanging throughout the cosmos.

“This work allows us to narrow down the best places to search for life,” added Rimmer, according to Phys.org. “It brings us just a little bit closer to addressing the question of whether we are alone in the universe.”

Distant galaxy forms stars at incredible pace, study reports

A newly discovered galaxy makes stars much, much faster than the Milky Way does.

Scientists working with Chile’s Atacama Large Millimeter/submillimeter Array (ALMA) have observed a galaxy that forms stars at an unprecedented rate, a new study published in Nature reports.

The distant “Monster Galaxy” — known as COSMOS-AzTEC-1 — came about roughly 2 billion years after the Big Bang. While it appears normal at first glance, it is unique because it generates over a thousand Suns worth of gas of stars each year.

That trait is important because, while scientists do not understand early galaxies, the new discovery could shed light on why certain systems form stars so fast.

When studying the new system, astronomers found that the clumpy gas inside of it has a stronger gravitational pull on itself than the force of the galaxy’s rotation from stars and supernovae. In addition, they also discovered it had two extra areas of gas-generating stars, rather than just one dense cloud of material.

“We found that there are two distinct large clouds several thousand light-years away from the center,” said lead author Ken-ichi Tadaki, a researcher at the Japan Society for the Promotion of Science and Japan’s National Astronomical Observatory, according to Space.com. “In most distant starburst galaxies, stars are actively formed in the center. So it is surprising to find off-center clouds.”

A team of international researchers found the galaxy while using ALMA’s 66 radio telescope dishes in the Chilean desert to look for signatures of carbon monoxide gas. Once they discovered it, they created a map based on what they found.

That showed the large, dense gas clumps inside AzTEC-1 are quite unstable and likely burn out within 100 million years of their formation. However, they form stars extremely quickly in that time.

Scientists are still not sure how galaxies like AzTEC-1 manage to build up so much gas before beginning their star formation, but they believe it could be the result of a galactic merger. Even so, as there is no evidence to support that process, more observations need to be done on such systems in the coming years to get a better idea of how they work.

“At this moment, we have no evidence of merger in this galaxy,” added Tadaki, according to Phys.org. “But by observing other similar galaxies with ALMA, we want to unveil the relation between galaxy mergers and monster galaxies.

Intermediate black holes can bring stars back to life

A new study reveals that medium-sized black holes are able to briefly reignite dead stars.

If a dead star passes close to a medium-sized black hole it can come back to life for a brief moment, according to a new study published on the preprint site Arxiv.org and accepted for publication in The Astrophysical Journal.

This finding comes from a group of international astronomers, who performed a series of computer simulations that revealed what happens when a burned-out stellar corpse — also called a white dwarf — moves by an intermediate-mass black hole.

After analyzing the data, researchers found that the hole’s strong gravity can stretch and distort the dwarf in such a way that the elements inside its core reignite for a few seconds.

Those so-called “tidal disruption events” can also create gravitational waves that, while not detectable by current technology, could be picked up for study in the future.

The new study is important for a few reasons, but one of the biggest is that it sheds light on medium-sized black holes, which have proven difficult to study. Though many smaller and larger holes are on record, the middle ones are not easy to pin down. As a result, the more information on them, the better.

“It is important to know how many intermediate mass black holes exist, as this will help answer the question of where supermassive black holes come from,” study co-author Chris Fragile, a professor of physics and astronomy at the College of Charleston in South Carolina, according to Space.com.“Finding intermediate mass black holes through tidal disruption events would be a tremendous advancement.”

Another reason the finding is important is because it shows how the sun could die in the distant future. Every star that begins its life with about 8 solar masses or fewer will end up as a superdense white dwarf, and analyzing our star in light could provide more insight into the universe’s larger mechanisms.

New Horizons sets its sights on Kuiper Belt object

For the first time in history, the New Horizons spacecraft has glimpsed images of the space object Ultima Thule.

The New Horizons spacecraft has glimpsed the mysterious Kuiper Belt object known as Ultima Thule for the first time.

After spending quite a bit of time observing Pluto, NASA’s New Horizons has a new course set towards the Kuiper Belt. More specifically, its goal is the distant object Ultima Thule — an object that sits roughly 44 AU from the Sun.

Though it is still 107 million miles from Ultima Thule, the craft’s Long Range Reconnaissance Imager managed to snap roughly four dozen images of the celestial body. It then sent that data back to Earth, where NASA scientists used it to create a composite image and discern the dim object from all the background stars.

That revealed Ultimate Thule sits where astronomers originally thought it did, showing New Horizons is right on track.

“The image field is extremely rich with background stars, which makes it difficult to detect faint objects,” said Hal Weaver, a New Horizons project scientist,  according to Gizmodo. “It really is like finding a needle in a haystack. In these first images, Ultima appears only as a bump on the side of a background star that’s roughly 17 times brighter, but Ultima will be getting brighter—and easier to see—as the spacecraft gets closer.”

There are two reasons the newly compiled picture is so important. Not only does it give new insight into the Kuiper Belt, but it is also marks the most distant images ever taken from Earth. In addition, New Horizons also showed it has the ability to detect its target, which means the astronomers will be able to adjust the craft if needed.

NASA reports that New Horizons will move past Ultima Thule on January 1, 2019. That passing will mark the most distant object ever visited by a human-built spacecraft and give even more insight into Ultima Thune.

“Our team worked hard to determine if Ultima was detected by LORRI at such a great distance, and the result is a clear yes,” said Alan Stern, a researcher at the Southwest Research Institute, according to Phys.org. “We now have Ultima in our sights from much farther out than once thought possible. We are on Ultima’s doorstep, and an amazing exploration awaits!”

STEVEs are not auroras after all, study reports

New research into Strong Thermal Emission Velocity Enhancements show that they are not auroras

New research on unique atmospheric effects known as Strong Thermal Emission Velocity Enhancements (STEVEs) show that they are not auroras, but rather a never-before-recorded atmospheric phenomenon.

Researchers first began to analyze the cosmic lights a few years ago when citizens posted images of them to a Facebook group known as Alberta Aurora Chasers.

Though the bands look like typical auroras, they do not blanket the night sky. Rather, they are narrow and shoot up in colorful ribbons. That unique property is what drew scientists to them.

Auroras occur when electrons and protons from Earth’s magnetosphere rain down onto the ionosphere. That then shoots off a range of colors, including green, red, and blue.

While STEVEs look like auroras, they have key differences that set them apart. Not only do they appear as ribbons with purple and white hues, but they also run from east to west, and sit closer to the equator than auroras. In addition, though auroras are visible every night in their regions, STEVEs can only be viewed a few times each year.

Even so, despite the differences researchers still believed that STEVEs came about through the same processes that create auroras. The new research refutes that.

“Our main conclusion is that STEVE is not an aurora,” said lead author Bea Gallardo-Lacourt, a researcher from the University of Calgary, according to Gizmodo. “So right now, we know very little about it. And that’s the cool thing, because this has been known by photographers for decades. But for the scientists, it’s completely unknown.”

To learn more about the phenomena, the team in the study used a network of ground-based All-Sky Images to analyze the light from a STEVE event to see if the light came about from a known or new process.

That revealed no traces of particle precipitation, a finding that suggests that STEVEs are not auroras. Their light likely comes about from a brand new mechanism that is not on record.

Researchers plan to further study the events in the near future.

“This is a light display that we can observe over thousands of kilometers from the ground,” said Liz MacDonald, a space scientist at NASA’s Goddard Space Flight Center who was not involved in the research, according to USA Today. “It corresponds to something happening way out in space. Gathering more data points on STEVE will help us understand more about its behavior and its influence on space weather.”

This new research is published in the Geophysical Research Letters.

Water ice confirmed on moon for first time

Astronomers have finally confirmed the presence of water ice on the surface of the moon.

For the first time in history astronomers have found definitive evidence of water-ice on the moon’s surface, according to a new study in the Proceedings of the National Academy of Sciences.

Researchers have long speculated that Earth’s natural satellite has ice on its surface. However, this is the first official confirmation. The frozen liquid sits at the north and south poles and is likely ancient, BBC News reports.

To find the ice, a team of international astronomers analyzed data gathered by India’s Chandrayaan-1 spacecraft. That showed the distribution is quite scattered. Most of the ice at the lunar south pole is in craters, and at the north pole it is much more widespread.

Those findings come from the Moon Mineralogy Mapper (M3) instrument aboard Chandrayaan, which identified three specific water-ice signatures on the moon.

Not only did it get the tell-tale reflective properties associated with ice, but it also measured the way its molecules absorb infrared light. That is important because it shows the substance is solid and not vapor.

“The abundance and distribution of ice on the Moon are distinct from those on other airless bodies in the inner solar system such as Mercury and Ceres, which may be associated with the unique formation and evolution process of our Moon,” wrote the researchers, according to Fox News.

Though the moon is quite hot during the day, ice can exist because, as the axis tilts, parts of the body never see sunlight.

The new finding supports past evidence that suggested the presence of surface ice at the Moon’s south pole. That is important because, if there is a substantial amount of ice, astronauts could one day harvest it during space missions. It may even help foster a future lunar base, and it could potentially be turned into hydrogen for rocket fuel as well.

Andromeda galaxy likely swallowed Milky Way’s sibling

Researchers discovered evidence that Andromeda likely collided with the Milky Way’s sister galaxy billions of years ago.

Scientists from the University of Michigan have found evidence that the nearby Andromeda galaxy clashed with and devoured the Milky Way’s long-lost sibling M32p, a new study in Nature Astronomy reports.

The Milky Way and Andromeda are linked because they are two of the largest galaxies in our small section of the universe. However, in the new study astronomers found that Andromeda once devoured the third largest member of the family roughly 2 billion years ago.

“Astronomers have been studying the Local Group — the Milky Way, Andromeda and their companions — for so long,” said study co-author Eric Bell, a professor of astronomy at the University of Michigan, according to Space.com. “It was shocking to realize that the Milky Way had a large sibling, and we never knew about it.”

The team made this new discovery by using computer simulations to reveal that almost all of the stars in the outer reaches of Andromeda’s “halo” — the roughly spherical region surrounding the galaxy’s disk — came from a single event.

That is important because scientists used that information to properly infer the properties of the largest of those long-dead galaxies.

That process, combined with recently created models, enabled the team to properly date the merger to roughly 2 billion years ago. In addition, they also managed to reconstruct some details from the long-dead galaxy.

That showed M32p was roughly 20 times the size of any galaxy the Milky Way has ever merged with. In addition, scientists believe that Andromeda’s satellite galaxy M32 — which is one of the most compact galaxies in the universe — is likely made up of the remains from M32p.

The timing of the ancient merger is important because it reinforces what scientists understand about galaxy formation. It also matches up with previous research that Andromeda merged with another large galaxy between 1.8 and 3 billion years ago.

In that way, the finding may help scientists better understand the mechanisms behind galaxy mergers and shed light on the way they evolved over time.

“The Andromeda Galaxy, with a spectacular burst of star formation, would have looked so different 2 billion years ago,” added Bell, according to Phys.org.