Andromeda galaxy was formed in 'recent' star crash: study

February 14, 2018
Calculating the birth date of the Andromeda galaxy has been a major challenge for astrophysicists

The Milky Way's neighbouring galaxy, Andromeda, was formed in a colossal crash between two smaller star systems no more than three billion years ago when Earth already existed, researchers said Wednesday.

Calculating the birth date of the galaxy has been a major challenge for astrophysicists given the vast age gap between the different stars it is made up of.

For the latest study, French and Chinese researchers led by Paris Observatory astronomer Francois Hammer used "the most powerful available computers in France" to crunch about a terabyte of data—the equivalent of two million 500-kilobyte photos.

This allowed them to zoom in on "the physical mechanisms of the Andromeda formation, so lifting the veil on its origin," the observatory said in a statement.

The results were published in the Monthly Notices of the Royal Astronomical Society.

Previous research had noted one major difference between our own galaxy and Andromeda—long considered twin clusters, the team pointed out.

In Andromeda, certain stars orbit erratically while in the Milky Way, all observe a simple rotation around the galaxy's centre.

Why?

The star agitation was due to the galaxy's "recent" formation, the team said.

The data showed that between seven and 10 billion years ago, two galaxies—one four times more massive than the other—found themselves on a collision course.

The team simulated both precursor ' trajectories and calculated that they fused between 1.8 billion and three billion years ago to forge Andromeda.

Two reconstructions of the event can be seen below:

Explore further: Stream of stars in Andromeda satellite galaxy shows cosmic collision

Related Stories

Hubble sees spiral in Andromeda

February 10, 2017

The Andromeda constellation is one of the 88 modern constellations and should not be confused with our neighboring Andromeda Galaxy. The Andromeda constellation is home to the pictured galaxy known as NGC 7640.

Dawn of a galactic collision

December 14, 2017

A riot of colour and light dances through this peculiarly shaped galaxy, NGC 5256. Its smoke-like plumes are flung out in all directions and the bright core illuminates the chaotic regions of gas and dust swirling through ...

Image: Hubble uncovers a mysterious dwarf galaxy

June 13, 2016

The drizzle of stars scattered across this image forms a galaxy known as UGC 4879. UGC 4879 is an irregular dwarf galaxy—as the name suggests, galaxies of this type are a little smaller and messier than their cosmic cousins, ...

Image: Hubble captures collision of two galaxies

October 23, 2017

This image, captured by the NASA/ESA Hubble Space Telescope, shows what happens when two galaxies become one. The twisted cosmic knot seen here is NGC 2623—or Arp 243—and is located about 250 million light-years away ...

Recommended for you

Active galactic nuclei and star formation

October 15, 2018

Most galaxies host a supermassive black hole (SMBH) at their nucleus. (A supermassive black hole is one whose mass exceeds a million solar-masses.) A key unresolved issue in galaxy formation and evolution is the role these ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Benni
1.4 / 5 (9) Feb 14, 2018
....in addition to this our two visible matter galactic halos are already touching:

https://io9.gizmo...04945980

......betch'a DM Cosmic Fairy Dust Enthusiasts never knew this. I won't bother explaining what this portends for the presence of the most abundant substance in the Universe that has never been found except within the print of the printed pages of Astronomy magazine.
nrauhauser
not rated yet Feb 14, 2018
Oh, Benni, did your Above Top Secret account get suspended? What strange stories you have to share.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.