Starship Asterisk*

Chris Peterson wrote:Way too small to be visible.

Do you mean "way too small to be invisible"? Er... "to be conspicuously absent"... Er...

The explanation I've heard for galactic centers being yellowish is that they contain older stars, as well as dust.

I've always wondered whether perhaps the light doesn't lose some energy as it leaves the gravity well, though.

-Noel

Spaquarain wrote:So, so cool. Great photo. But, if the center of all galaxies is a black hole-why is it yellow? I know this question is VERY amaturish.

Because the black hole's apparent size is much, much smaller than even a single pixel in the image. Way too small to be visible.

John Hamilton wrote:Your APOD for 1/13/11 depicted and listed NGC3521 as a "mear" 35 million light years away. Thought your readers would like to know that traveling as fast as we could in available rocketry, it would take us 560,000 years to arrive there from Earth . That is not mear, but a much larger distance.

Sorry John,
You are just a little off there
Light travels at 186,000 miles per second
60sec X 60min X 24hrs X 365 days = 1 year X 186,000 =
1,818,371,625,696,000,000 or roughly 1.818 Quintillion miles in a light year
Then by 35 million
63,643,006,899,360,000,000,000,000 or roughly 63.646 Septillion miles
Our fastest probe is traveling at 40,850 mph X 24hrs X 365 days
It covers 357,846,000 miles per year
At that rate, it would take
177,850,267,711,138,310.89 roughly 177.85 Quadrillion years to reach it.

So, so cool. Great photo. But, if the center of all galaxies is a black hole-why is it yellow? I know this question is VERY amaturish.

Given that we haven't found a way to break through the limits of relativity, it's right where it is in all ways that matter.

For a long time I tended to imagine that there's a "right now" that somehow transcends relativity, so that I could imagine where that galaxy is "right now" (opposed to where we see it). I've come very slowly to think that there really isn't a use for such a concept, unless we leave the dimensions of this universe entirely behind...

What if, for example, we could somehow learn (but, you see, we CAN'T) that a star had exploded (was going to explode?) and was (would be) sending a gamma ray burst in our direction. Might we build a space probe that would go out far enough to erect a shield to "shade" the Earth?

And in another random thought... if someone is standing across the room from us, we can see them and they can see us, right now (whatever that means). Not so (beyond the obvious reasons) with someone light-years away. We are essentially looking through a cosmic one-way glass, it seems. We may be looking at one another, but neither can say what the other will do until the crossing is made at the speed of light.

Inasmuch as it's hard to talk to someone on a satellite link with a 1 second delay, imagine the difficulty in talking to people we might send to Mars (okay, not THAT hard to imagine, it's been shown in Sci Fi films such as Red Planet). Basically, at some point you're on your own and you just can't make a call and must use eMail.

The distance where "you're on your own" may be a few yards for physical things, and it may be a few million miles for information.

Is this proof that our imaginations, which seem unbounded by these mere laws of physics, live outside the physical reality of our universe? Food for thought. Yesterday.

-Noel

I am wondering, when the distance is listed, like 35 million miles, is that where the projected location of the galaxy is or where it was when the light started to make its way to us?

Which edge of that galaxy is nearer us? From the way light reflects and is scattered I think the upper edge is nearer. It would be interesting to have such details provided for as many APODs as possible, BTW.

D'ohh!! Five seconds later I realize that those dark areas are shadows, so the *lower* edge is nearer.

Wow! To me it looks like a lot of star making dust in this galaxy!

John Hamilton wrote:
Your APOD for 1/13/11 depicted and listed NGC3521 as a "mear" 35 million light years away. Thought your readers would like to know that traveling as fast as we could in available rocketry, it would take us 560,000 years to arrive there from Earth . That is not mear, but a much larger distance.

beyond wrote:

On a Galatic scale, 35 million light years is a piddleing amount.

Why It's just a hop-skip and a jump away

On a Galatic scale, 35 million light years is a piddleing amount. Why It's just a hop-skip and a jump away

Your APOD for 1/13/11 depicted and listed NGC3521 as a "mear" 35 million light years away. Thought your readers would like to know that traveling as fast as we could in available rocketry, it would take us 560,000 years to arrive there from Earth . That is not mear, but a much larger distance.

Stunning image and excellent prosessing of Robert Gendler.
Greetings
César

NGC 3521 Close Up

Explanation: Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years distant, toward the constellation Leo. Spanning some 50,000 light-years, its central region is shown in this dramatic image, constructed from data drawn from the Hubble Legacy Archive. The close-up view highlights this galaxy's characteristic multiple, patchy, irregular spiral arms laced with dust and clusters of young, blue stars. In constrast, many other spirals exhibit grand, sweeping arms. A relatively bright galaxy in planet Earth's sky, NGC 3521 is easily visible in small telescopes, but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like M66 and M65.

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