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Hubble Ultra Deep Field... in 3D!

"47 billion lightyears" .... err.... WHAT? Explain what he's talking about please smart people.
 
Cool, MM. Thanks.

At about 4:15 the narrator says, "...and filters that allowed more light through than ever before..." I don't understand. Don't filters reduce the amount of light received? If it is meant that "looser" filters are being used, why not remove the filters altogether?
 
Might be better efficiency - compare a filter that lets through 50% of light between 500 and 600nm and no light elsewhere, and one that lets through 95% between 500 and 600nm and no light elsewhere.
 
edd said:
Might be better efficiency - compare a filter that lets through 50% of light between 500 and 600nm and no light elsewhere, and one that lets through 95% between 500 and 600nm and no light elsewhere.
Click to expand...
That's a reasonable explanation. But...

If they were pointing Hubble at an "empty" portion of the sky, why limit the band of light accepted? Doesn't such a limit put a cap on what one might learn?

That said, there might be technological constraints that I don't know about but the question remains.
 
Unfiltered astronomical observations are a bit uncommon. You usually gain something by having a few observations in different bands over one unfiltered observation, and it makes comparison to other observations a bit easier and it probably makes it easier to calibrate the actual luminosity you're measuring. For example, by having the UDF in its four bands you can compare more easily to other Hubble observations, and you get colours of objects which can be used to estimate distances and other properties of the sources.
You might well see more faint objects with an unfiltered observation, but you won't necessarily know much about those faint objects.
 
I have the Hubble Ultra Deep Field as my desktop. Thank you so much for posting this. Don't feel bad, JFrankA, I got a bit misty-eyed myself.
 
I always like the ominous operatic background music to these kinds of videos.
If space has a soundtrack, I hope it's like that.
(Or maybe Rush)
 
I like this stuff.

But, seriously, "most important image ever taken?"

How about The Pale Blue Dot?

or:
- a picture of the Trinity blast
- that Tiananmen square picture
- or...

Ooh!

There's a good one going on right now at sciforums.com

excuse me while I go peruse... :D
 
Third Eye Open said:
"47 billion lightyears" .... err.... WHAT? Explain what he's talking about please smart people.
Click to expand...

This website has a nice explanation of several different distance/time measurements that can be applied to the universe. Because space itself is changing its size, it's a little confusing at times to say clearly and simply how far apart things are or how long ago they happened.

I used to show my students another of the fellow's videos, "The Most Important Image Ever Taken" and it rarely failed to bring tears to the eyes of at least one kid. I'll switch to this one now, it's much clearer and better edited.

The only one that compares in impact is the Tiananmen Square video of the man with his groceries. It's too bad that that is the only part of the month long protests that anyone seems to have remembered though. It has nothing to do with physics, but if history teachers can't be bothered to teach this stuff, then someone needs to do it.
 
At about 2.20 it says that these galaxies are moving "..in some cases, faster than the speed of light". Can someone please explain?

Awesome video, btw.
 
longfellow said:
I have the Hubble Ultra Deep Field as my desktop. Thank you so much for posting this. Don't feel bad, JFrankA, I got a bit misty-eyed myself.
Click to expand...

As do I, and the Pale Blue Dot video has exactly the same effect on me. The very definition for me of numinous.
 
ugot2bekidding said:
At about 2.20 it says that these galaxies are moving "..in some cases, faster than the speed of light". Can someone please explain?

Awesome video, btw.
Click to expand...

Pretty sure it means in relation to earth, they are moving away from us faster then the speed of light. So if we're going <---- and those galaxies are going ----> faster then half the speed of light, then those galaxies are moving --------> away from us faster than the speed of light.

Though i could be completely wrong on this.
 
It's a bit fiddly. For one thing, you don't generally count the observer as moving - you don't talk about us 'going <-----'. And it isn't just a result of two velocities adding as you might think from reading thull's post - but it is subtly different from straightforward 'traditional' faster than light travel.

The other point I always try to make is that nothing is going faster than light. The distance between things might be growing at a rate that is faster than light could cover it, but there's no overtaking of light involved, which is the big no-no, and you can't use the universe's expansion to get anywhere.

Ned Wright's FAQ - http://www.astro.ucla.edu/~wright/cosmology_faq.html#FTL - also covers it.
 
ugot2bekidding said:
At about 2.20 it says that these galaxies are moving "..in some cases, faster than the speed of light". Can someone please explain?

Awesome video, btw.
Click to expand...

It's a case of the expansion of space between us and the object happening faster than light can cover the distance. Noone is breaking any speed limits.. :)

As the expansion seems to be accellerating this means that our night sky eventually will become black.
 
ugot2bekidding said:
At about 2.20 it says that these galaxies are moving "..in some cases, faster than the speed of light". Can someone please explain?

Awesome video, btw.
Click to expand...

It's the objects in the universe (matter and energy and such) that cannot go faster than the speed of light. Space itself can grow at a faster rate. This idea is part of a common explanation for why the universe is so homogeneous, that the universe was small enough for various parts of it to communicate with one another at one point but then expanded extremely rapidly (the inflationary model) to produce what we see today, ultimately.
 
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