The Milky Way May Have Already Collided With Another Galaxy
Astronomers predict that our Milky Way galaxy is on a collision course with Andromeda, and we’ve got just a few billion years to brace for impact. However, the Milky Way might have a history of smashing up other galaxies. A new analysis suggests that our galaxy may have collided with a recently discovered dwarf galaxy called Antlia 2.
Scientists discovered Antlia 2 in late 2018 in orbit of the Milky Way. It’s an unusual object due to its extremely low density. While it’s about the same size as the Large Magellanic Cloud satellite galaxy, it’s about 10,000 times more diffuse. According to the team from the Rochester Institute of Technology, the current state of Antlia 2 and perplexing ripples in the Milky Way’s hydrogen gas disk (discovered about ten years ago) could be explained by a collision between the two galaxies. Of course, Antlia 2 came out of it much worse off than the Milky Way.
Using data collected by the European Space Agency’s Gaia satellite, Sukanya Chakrabarti and her team calculated the past trajectory of Antlia 2. Based on the models the team generated, Antlia 2 may have collided with the Milky Way several hundred million years ago.
We often think of galaxies as dense, unified objects with wall-to-wall stars. However, galaxies are mostly empty space. When they “collide,” it’s unlikely that any two stars will actually run into each other. Instead, the gravitational interaction may fling stars out into deep space or cause them to migrate from one galaxy to the other. Clouds of dust and gas may also merge, causing an uptick in star formation.
So, the Milky Way is still largely the same as it was before running into Antlia 2. However, the smaller galaxy was wrecked by the gravity of its larger neighbor. That accounts for the very diffuse current state. The team also used its models to rule out another alleged candidate for the cause of those ripples in the Milky Way: the Sagittarius dwarf galaxy. The model projects no likely collisions between that galaxy and the Milky Way in the past. This work could solve the ripple mystery.
Scientists hope that studying Antlia 2 and its orbit will reveal some clues to the nature of dark matter, a separate mystery scientists are still a long way from unraveling.
Continue reading
Protect Your Online Privacy With the 5 Best VPNs
Investing in a VPN is a smart choice right now, but the options are vast. To help narrow things down a bit, we've rounded up five of our very favorite consumer services.
RISC-V Tiptoes Towards Mainstream With SiFive Dev Board, High-Performance CPU
RISC V continues to make inroads across the market, this time with a cheaper and more fully-featured test motherboard.
The PlayStation 5 Will Only Be Available Online for Launch Day
The PlayStation 5 isn't going to be available in stores on launch day, and if you want to pick up an M.2 SSD to expand its storage, you'll have some time to figure out that purchase.
ARMing for War: New Cortex-A78C Will Challenge x86 in the Laptop Market
ARM took another step towards challenging x86 in its own right with the debut of the Cortex-A78C this week. The new chip packs up to eight "big" CPU cores and up to an 8MB L3 cache.