The Naked Scientists

The Naked Scientists Forum

Author Topic: Are they right about the G2 gas cloud?  (Read 1439 times)

Offline jeffreyH

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 3913
  • Thanked: 52 times
  • The graviton sucks
    • View Profile
Are they right about the G2 gas cloud?
« on: 06/12/2014 00:05:33 »
The latest news can be found at http://news.nationalgeographic.com/news/2014/11/141106-space-g2-black-hole-science/

What about the conclusions that they reached? The star is assumed to be relatively small in cosmological terms so why would it not shed its cloud of gas due to strong tidal forces. Does this really make sense or do we misunderstand gravity?


 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: Are they right about the G2 gas cloud?
« Reply #1 on: 06/12/2014 19:40:53 »
I don't even know how they can be so sure it didn't, well, partially at least?
How good is their resolution?

"The case for a massive black hole at the center of our Galaxy has been argued over the past few decades, however it has not been previously possible to prove this tantalizing hypothesis. In principle the stars in the vicinity of the Galactic Center can be used as ``test particles" to probe the for the presence of a central dark mass.

However, the density of stars in this region is so high that previous studies have reached an impasse due to limitations in angular resolution. With the ability to carry out diffraction-limited imaging at Keck, Prof. Ghez has mapped the Galactic Center with unprecedented angular resolution. These observations reveal stars moving at apparent speed as high as 12,000 km/sec (~4% the speed of light!) whose orbits implies the presence of 3.7 million times that mass of the Sun of dark matter interior to a radius of about 0.0002 pc (6 light hours or 600 Rs).

This exceeds volume averaged mass densities inferred for any other galaxy and leads to the conclusion that our Galaxy harbors a massive central black hole. If galaxies as inactive as our own support a central black hole, then one might assume that such objects can be found at the centers of all galaxies!"

I'm sure they see something, now assuming that it might be a star hidden inside the gas cloud they define. Whatever gravity such a wandering star has it has to counteract all tidal forces emanating from the massive black hole, if they are correct.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: Are they right about the G2 gas cloud?
« Reply #2 on: 06/12/2014 19:43:22 »
Then again, wouldn't it depend on what type of black holes the star meets? Think I saw some ideas in where you might pass a event horizon without tidal forces?
 

The Naked Scientists Forum

Re: Are they right about the G2 gas cloud?
« Reply #2 on: 06/12/2014 19:43:22 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums