Finsk astronom utforskar krocken Vintergatan-M31

Krockar, krockar inte, krockar… ja, hur går det med beräkningen av stora smällen mellan Vintergatan och M31, Andromedagalaxen? Nya uppgifter från Hubble- och Gaia-teamen sätter stort ? för trafikolyckan om 4-5 miljarder år. Jag återger delar av senaste messet från HST på engelska, det klarar vi:

“Over a decade’s worth of NASA/ESA Hubble Space Telescope data was used to re-examine the long-held prediction that the Milky Way galaxy will collide with the Andromeda galaxy in about 4.5 billion years. The astronomers found that, based on the latest observational data from Hubble as well as the Gaia space telescope, there is only a 50-50 chance of the two galaxies colliding within the next 10 billion years. The study also found that the presence of the Large Magellanic Cloud can affect the trajectory of the Milky Way and make the collision less likely. The researchers emphasize that predicting the long-term future of galaxy interactions is highly uncertain, but the new findings challenge the previous consensus and suggest the fate of the Milky Way remains an open question.

As far back as 1912, astronomers realized that the Andromeda galaxy — then thought to be only a nebula — was headed our way. A century later, astronomers using the NASA/ESA Hubble Space Telescope were able to measure the sideways motion of Andromeda and found it was so negligible that an eventual head-on collision with the Milky Way seemed almost certain.

Credit: NASA, ESA, STScI, Till Sawala (University of Helsinki), DSS, J. DePasquale (STScI)

A smashup between our own galaxy and Andromeda would trigger a firestorm of star birth, supernovae, and maybe toss our Sun into a different orbit. Simulations had suggested it was inevitable.

However, a new study using data from Hubble and ESA’s Gaia suggests this may not necessarily be the case. Researchers combining observations from the two space observatories re-examined the long-held prediction Milky Way – Andromeda collision, and found it is far less inevitable than astronomers had previously suspected. 

“We have the most comprehensive study of this problem today that actually folds in all the observational uncertainties,” said Till Sawala, astronomer at the University of Helsinki in Finland and lead author of the study, which appears today in the journal Nature Astronomy.

His team includes researchers at Durham University, United Kingdom; the University of Toulouse, France; and the University of Western Australia. They found that there is approximately a 50-50 chance of the two galaxies colliding within the next 10 billion years. They based this conclusion on computer simulations using the latest observational data.”

Sammanfattningsvis: I HST-pressmesset bedöms risken/chansen för en krock kommande 10 miljarder år som fifty-fifty.

Till Sawala

Jesper lockar till studier

På Instagram propagerar vår SN-professor Jesper Sollerman i Stockholm för studier vid universitet.

Instagramkontot här.

“Kosmisk tornerspel”: astronomer observerar galaxer i kosmisk kamp

Astronomer har för första gången bevittnat en våldsam kosmisk kollision där en galax genomborrar en annan med intensiv strålning. Forskarnas resultat, som publicerats i tidskriften Nature, visar att denna strålning hämmar den skadade galaxens förmåga att bilda nya stjärnor. I den nya studien kombinerades observationer från European Southern Observatory’s Very Large Telescope (ESO:s VLT) och Atacama Large Millimeter/submillimeter Array (ALMA), vilket avslöjar intrikata detaljer i denna galaktiska strid.

Pressmeddelandet med bilder och filmer finns på:
https://www.eso.org/public/sweden/news/eso2509/