Background light suggests many stars 'outside galaxies'

[klr]

A new study of the universe's background light has suggested that as many as half its stars might be hidden in the space between galaxies.

Measurements were made by two cameras sent beyond the atmosphere on a rocket.

After subtracting all the interference from dust and galaxies, the leftover light has ripples in it, which the study's authors ascribe to lone stars, flung out during galactic collisions.

Other scientists believe it comes from whole galaxies that are very distant.

The new results are published in the journal Science.

Prof Jamie Bock from Nasa's Jet Propulsion Laboratory, one of the report's authors, described the extragalactic background light (EBL) as "kind of a cosmic glow".

"It's very faint - but basically the spaces between the stars and galaxies aren't dark. And this is the total light made by stars and galaxies during cosmic history," Prof Bock told the BBC.

Earlier measurements from rockets and satellites had shown that there was more fluctuation in this background than the sum total of known galaxies could explain.

At least two proposals were made to account for the extra light: it might come from very early, distant galaxies that formed when the universe was much younger, or it might come from stray stars outside galactic boundaries.

Prof Bock's team set out to study the EBL in detail, in terms of its colour and its distribution, to try and settle the debate.

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more: http://www.bbc.com/news/science-environment-29917082

[JimC]

It would be a lonely place, to be on a planet circling a star in the deeps between the galaxies...

[klr]

It would be a lonely place, to be on a planet circling a star in the deeps between the galaxies...

I can imagine intelligent beings on such a world arguing about those few scattered dots of light in the night sky. A bit like the 1920's argument about whether the Milky Way was the whole universe or not.

[Brian Peacock]

It would be a lonely place, to be on a planet circling a star in the deeps between the galaxies...

Well we can hardly say that we enjoy a warm relationship with our immediate neighbours either.

"So wownwy... "

[klr]

It would be a lonely place, to be on a planet circling a star in the deeps between the galaxies...

Well we can hardly say that we enjoy a warm relationship with our immediate neighbours either.

"So wownwy... "

Yes, we've never bothered to go to the local interstellar planning office on Alpha Centauri. Who knows what we might find there?

... a lame Hitchhiker's reference

[Clinton Huxley]

Stars from outside the galaxy, coming over here, taking our stars jobs? Milky Way Independence Party won't stand for it.

[mistermack]

What with supermassive black holes at the centre of nearly all galaxies, you would expect some stars to be flung out clear of the galaxy, if they pass by very close, missing it by a narrow margin.

Not that I've done the maths or anything. That's just my guess. And when two galaxies "collide", that might happen a lot, as stars in steady orbits are pulled into new directions by the second black hole.

[pErvinalia]

It would be a lonely place, to be on a planet circling a star in the deeps between the galaxies...

I can imagine intelligent beings on such a world arguing about those few scattered dots of light in the night sky. A bit like the 1920's argument about whether the Milky Way was the whole universe or not.

They wouldn't have constellations, and perhaps as result might have even avoided religion! Sounds like heaven!