APOD: Unusual Starburst Galaxy NGC 1313 (2010 Mar 30)

[dduggan47]

I'd have thought that since we're dealing with light, that distance and time are pretty much the same thing. We're seeing the object as it looked 15 million years ago.

What am I missing?

It's a question of semantics. "Now" has formal meanings in physics, and can be used different ways. It is perfectly correct to talk about "now" in terms of the relationship between two objects and their light cones. In a very real sense, we are seeing every object as it is "now", even if it is 15 million light years away. It doesn't matter if the light took 15 million years to reach us- we are seeing it as it is now in our own frame of reference. In that sense, what is happening "now" if our clocks could somehow be synchronized (which is a difficult concept) is actually happening 15 million years in the future.

It is also possible to use "now" as if there were a universal clock. It really comes down to the math chosen for an analysis, and it's not so clear that either way of using "now" has a better or more accurate physical meaning than the other.

Got it. Thank you, Chris.

[neufer]

I believe this Starburst Galaxy NGC-1313 is the best proof I've seen yet that Black Holes do wander around out there in the Universe. One passed close enough to this once previously Barred Spiral Galaxy and literally tore it apart. It caused massive gravitational waves to pass thru it causing all the gas & dust compression into the rampant Star urst Formation we see today. Once this Galaxy finally pulls back together it is going to be very bright. Just my opinion.

The largest black hole only has a 18 million solar mass gravitational field whereas a galaxy has almost a trillion solar mass gravitational field.

How about wandering blobs of dark matter instead?

[wonderboy]

This galaxy should be called Rearing Horse Galaxy. It looks like a horse on its hind legs.

Or.................. a dog giving someone a paw lol. The dogpaw galaxy sounds better anyway.

[wonderboy]

I like to think I understand the vastness of the universe and how something so big can seem so small. A blackhole that wandered close to a galaxy would never affect it in such a way. if it did it would have to be some blackhole a scary sight indeed. See my theory on how the universe works and you'll understand how my mind works .