Feeds

Suffering SPITZER! Boffins discover Milky Way's MISSING ARMS

New study affirms our galaxy has FOUR spiral arms

Remote control for virtualized desktops

Pic For years, boffins have been arguing over whether our galaxy has four spiral arms or just two, as seen by NASA's Spitzer Space Telescope.

Artist's impression of the Milky Way

You spin me right round ... an artist's impression of the Milky Way

The only way to confirm the theory is to try to figure out where the stars are and their distances from us, since we're on the inside of the galaxy, making it tough to see what it might look like from the outside.

Now a new 12-year study has reaffirmed the theory that the Milky Way is a four-armed spiral galaxy, as originally hypothesised in the 1950s. Back then, astronomers used radio telescopes to map the galaxy, focusing on clouds of gas in which new stars are born, and deduced that there were four arms.

That theory was thrown into debate when Spitzer searched for the infrared light emitted by stars and announced in 2008 that it had spotted around 110 million of them, but only found evidence of two spiral arms.

The latest study is part of the Red MSX (RMS) Survey conceived by the University of Leeds to systematically search the entire galaxy for massive young stellar objects. Using several radio telescopes in Australia, the US and China, distances and luminosities of these massive stars were calculated, showing a distribution across four spiral arms.

"It isn't a case of our results being right and those from Spitzer's data being wrong – both surveys were looking for different things," said Professor Melvin Hoare, a co-author of the paper. "Spitzer only sees much cooler, lower mass stars – stars like our Sun – which are much more numerous than the massive stars that we were targeting."

Massive stars are much less common because they only live for a short time, galacticly speaking, around 10 million years. That shorter lifespan could be the answer to the discrepancy in the results.

"Lower mass stars live much longer than massive stars and rotate around our galaxy many times, spreading out in the disc. The gravitational pull in the two stellar arms that Spitzer revealed is enough to pile up the majority of stars in those arms, but not in the other two," explained Professor Hoare. "However, the gas is compressed enough in all four arms to lead to massive star formation.

"Star formation researchers, like me, grew up with the idea that our Galaxy has four spiral arms. It's great that we have been able to reaffirm that picture."

The full study, "The RMS survey: galactic distribution of massive star formation" was published in the Monthly Notices of the Royal Astronomical Society. ®

Top 5 reasons to deploy VMware with Tegile

More from The Register

next story
Renewable energy 'simply WON'T WORK': Top Google engineers
Windmills, solar, tidal - all a 'false hope', say Stanford PhDs
FORGET the CLIMATE: FATTIES are a MUCH BIGGER problem - study
Fat guy? Drink or smoke? You're worse than a TERRORIST
Rosetta probot drilling DENIED: Philae has its 'LEG in the AIR'
NOT best position for scientific fulfillment
SEX BEAST SEALS may be egging each other on to ATTACK PENGUINS
Boffin: 'I think the behaviour is increasing in frequency'
HUMAN DNA 'will be FOUND ON MOON' – rockin' boffin Brian Cox
Crowdfund plan to stimulate Blighty's space programme
Post-pub nosh neckfiller: The MIGHTY Scotch egg
Off to the boozer? This delicacy might help mitigate the effects
I'M SO SORRY, sobs Rosetta Brit boffin in 'sexist' sexy shirt storm
'He is just being himself' says proud mum of larger-than-life physicist
NASA launches new climate model at SC14
75 days of supercomputing later ...
Britain's HUMAN DNA-strewing Moon mission rakes in £200k
3 days, and Kickstarter moves lander 37% nearer takeoff
prev story

Whitepapers

Why cloud backup?
Combining the latest advancements in disk-based backup with secure, integrated, cloud technologies offer organizations fast and assured recovery of their critical enterprise data.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Managing SSL certificates with ease
The lack of operational efficiencies and compliance pitfalls associated with poor SSL certificate management, and how the right SSL certificate management tool can help.
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.