Spiral galaxies bigger than thought

[Waspie_Dwarf]

Spiral galaxies like Milky Way bigger than thought, says CU-Boulder study

Let’s all fist bump: Spiral galaxies like our own Milky Way appear to be much larger and more massive than previously believed, according to a new University of Colorado Boulder study by researchers using the Hubble Space Telescope.

CU-Boulder Professor John Stocke, study leader, said new observations with Hubble’s $70 million Cosmic Origins Spectrograph, or COS, designed by CU-Boulder show that normal spiral galaxies are surrounded by halos of gas that can extend to over 1 million light-years in diameter. The current estimated diameter of the Milky Way, for example, is about 100,000 light-years. One light-year is roughly 6 trillion miles.

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[Taun]

I've heard that there was a halo of stars around most (if not all galaxies), but it never dawned on me that gas/dust would be there as well..

Are they sure about that 1 million LY halo?... That seems quite a bit larger than I would think it would be - due to interferance from other galaxies if nothing else... That's 2/3rds of the way to our galaxy (from Andromeda)...

Edited June 28, 2013 by Taun

[Waspie_Dwarf]

Are they sure about that 1 million LY halo?...

They wouldn't have published if they weren't

That seems quite a bit larger than I would think it would be - due to interferance from other galaxies if nothing else...

By interference I assume you mean gravitational disruption, What are you basing your assumptions on?

That's 2/3rds of the way to our galaxy (from Andromeda)...

Actually, as they are saying a million ly diameter, that give us a radius of half a million ly for each galaxy. Distance to Andromeda is 2.5 million ly so that is only 40% of the distance.

The Milky Way and Andromeda (like many galaxies) have dwarf satellites orbiting comparatively closely (the Milky Way has at least 15 {including the 2 Magellanic Clouds} and Andromeda has at least 14) if these satellite galaxies don't cause gravitational disruption, why should galaxies much further away?

[Taun]

They wouldn't have published if they weren't

By interference I assume you mean gravitational disruption, What are you basing your assumptions on?

Actually, as they are saying a million ly diameter, that give us a radius of half a million ly for each galaxy. Distance to Andromeda is 2.5 million ly so that is only 40% of the distance.

The Milky Way and Andromeda (like many galaxies) have dwarf satellites orbiting comparatively closely (the Milky Way has at least 15 {including the 2 Magellanic Clouds} and Andromeda has at least 14) if these satellite galaxies don't cause gravitational disruption, why should galaxies much further away?

diameter/radius (oops)

[NatureBoff]

Spiral galaxies like Milky Way bigger than thought, says CU-Boulder study

The article states:

The material for galaxy halos detected by the CU-Boulder team originally was ejected from galaxies by exploding stars known as supernovae, a product of the star formation process, said Stocke of CU-Boulder’s astrophysical and planetary sciences department. “This gas is stored and then recycled through an extended galaxy halo, falling back onto the galaxies to reinvigorate a new generation of star formation,” he said. “In many ways this is the ‘missing link’ in galaxy evolution that we need to understand in detail in order to have a complete picture of the process.”

Surely this is an understatement. He doesn't even venture to mention about the biggest problem in spiral galaxies that there is, i.e. The Galaxy Rotation Problem.

The discrepancy between the curves can be accounted for by adding a dark matter component to the galaxy.

Is it too much to link this research in with that of another? Cosmic Giants Shed New Light on Dark Matter

Edited June 29, 2013 by RingFenceTheCity