Scientists find monster black holes, biggest yet

Originally posted by Shugo
I would proceed with this question then, would a black hole be able to be detected via an infrared telescope? Surely there has to be another method of detection other than stellar orbits?

The smallest black hole we've ever indirectly observed is about 2.8 times the mass of the sun. We think that's close to the lower limit for a stable black hole, maybe down to roughly 2.5 solar masses or perhaps a little smaller could be found in the future.

Such black holes probably can't be observed directly, the hawking radiation would be far too weak. They can be observed indirectly by stars orbiting them, or if they are sucking in a gas cloud in which case we might see gamma rays from accelerated particles just outside the event horizon, or in rare cases we might observe them act as a gravitational lens and observe them indirectly that way.

There are hypothetical black holes created in the big bang that theoretically could be much smaller than 2 solar masses, but none have ever been observed:

Black Hole

To have a Hawking temperature larger than 2.7 K (and be able to evaporate), a black hole needs to be lighter than the Moon (and therefore a diameter of less than a tenth of a millimeter).[85]

However because they "evaporate" I doubt they are still around. But we are looking for them just in case, so far unsuccessfully.

If these black holes are lighter than the moon, the temperature could exceed the cosmic microwave background and we might be able to observe them directly with a newish telescope:

By their very nature, black holes do not directly emit any signals other than the hypothetical Hawking radiation; since the Hawking radiation for an astrophysical black hole is predicted to be very weak, this makes it impossible to directly detect astrophysical black holes from the Earth. A possible exception to the Hawking radiation being weak is the last stage of the evaporation of light (primordial) black holes; searches for such flashes in the past has proven unsuccessful and provides stringent limits on the possibility of existence of light primordial black holes.[88] NASA's Fermi Gamma-ray Space Telescope launched in 2008 will continue the search for these flashes.

An evaporating mini black hole will briefly radiate many times brighter than our sun in the gamma ray spectrum, if such things are still around. But like I said, if they evaporate, why would they still be here? I suspect that's why we've never seen one and I won't be shocked if we do, but maybe a little surprised.

reply to post by Angelic Resurrection


You are IMO more right than you probably even know.
A day will come when "we" finally find out that space, time, matter/anti-matter, gravity etc. are ALL different states of the same darn "thing" and that it is only our perception of that "thing" thats confusing us. Mark my words ATS!

Edit:

"Forever" tried to tell us: "Time is on our side".
You recite this knowing and you find it all.
...
While all we did was to divide (Breaking down the whole).
We never looked at what we found (Holograms within).
While we relied on space and time (Noone here can know).
At last we looked at what we found.

IT--

Pics or it didn't happen.

Originally posted by CaptChaos
Black holes highlight a situation, common today in astrophysics, where the object under investigation cannot be seen directly. This situation is pure heaven for the crowd of mathematical theorists who have hijacked physics from the natural philosophers and experimentalists. The sainted Einstein seems to have initiated the hijacking with that oxymoron, the “thought experiment.” But problems arise when thoughts are governed by a limited set of beliefs or dogmas and unchecked by direct observation or experiment. The result can be – and generally is – science fiction. University libraries and popular science magazines are full of it at the start of this new millennium.

You are just pissed off that the math is over your head. Or perhaps the equations we have point to something you can't intuitively grasp or want to believe.

I notice this in this site. That people who are most against the applied math in science are typically the ones who can't grasp the math. For instance, the thread on "Vortex Based Mathematics".