Friends, on Tuesday, scientists unveiled humanity's deepest ever peep into the visible universe. From the ground, the spot of space they studied seems empty and desolate. But when Hubble focused its sensitive eyes there for a million seconds, 10,000 galaxies came into view--some more than 13 billion light years away. It's the farthest (and furthest back in time) that human eyes have ever seen.
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Today's Knowledge
How Many Galaxies Are There?
If a single image can reveal 10,000 galaxies, just how many galaxies are there? How
many "billions and billions" of stars light the night sky?
Hubble scientists say their mind-boggling picture is like a "core sample" of the universe, made of light instead of Arctic ice. Imagine, the scientists say, that you're looking through an 8-foot-long soda straw, where each galaxy you see is a different distance from the Earth.
Remember, too, that you're looking back in time, as light from a galaxy 13 billion light years away takes 13 billion years to get here. Those 10,000 galaxies are spread both through space and 13 billion years of cosmic history--all packed into a slice of sky just one-tenth of the diameter of the full moon.
So, how many 8-foot-long straws would Hubble have to suck the universe through to taste the entire sky? According to the experts, about 12.7 million. They say the plucky telescope would need about a million years of uninterrupted time to make the images, too.
If each of those 12.7 million straws sucked in another 10,000 galaxies, we'd have about 127 billion galactic neighbors. Some estimates count on only 100 billion galaxies showing up in the census. Others think we'd find five times that.
It's best not to even think about how many stars that is. On a dark night in the country, you can see a few thousand, and that's humbling enough. Yet astronomers guess that there are anywhere from 100 billion to 1 trillion stars in the Milky Way alone. Multiply the low number by 100 billion galaxies and you get at least 10,000,000,000,000,000,000,000 stars.
The real number could be ten times that. Or a hundred times that. One NASA site puts the figure at a "zillion." No one knows. Astronomers are used to working with scary numbers, but when it comes to counting the stars in the firmament, most say that counting all the grains of sand from all the deserts and beaches of the world would be easier.
And just think about how far we have come (in technology) in just the past 100 years. Now if another civilization has just 1000 years on us(which is nothing), imagine their capabilities.
what if we end up being the aliens? millions of years from now abducting and doing tests on primitive alien civilizations.
for some odd reason, while the word "Ganya" was still just a thought-dropping in my head, I thought it'd only be four letters. But apparently it's five. yep.
Dekka00 said this in post #4 : what if we end up being the aliens? millions of years from now abducting and doing tests on primitive alien civilizations.
There are people who believe in aliens.... never listened to one of those radio hanels where they talk about their "experiences", eh? It's kind of funny..... no,.... hilarious!
It is folly to punish your neighbor by fire when you live next door.
Publilius Syrus
To think that we are alone is arrogant at the least and borderline idiotic. IMO that is. Anyone read The Day After Roswell? What did you think? Now tell me that we haven't been visited.
I believe that music is the ultimate expression of my soul.
For every facet of my humanity, there is a sound that can touch my soul, in a way that words cannot express. ---Outsider
wow that picture is beautiful... set it as my background
for some odd reason, while the word "Ganya" was still just a thought-dropping in my head, I thought it'd only be four letters. But apparently it's five. yep.
Man, this thread is old, but I just found it earlier today by accident. I also downloaded that pic, and have it as my desktop now. (like Dekka did two years ago)
It got me to thinking about light, and how it travels, and how I have always wondered how it keeps from dissipating or diffusing. I guess I don't understand light.
I know if you go into the ocean, not very deep, the light hits the water, gets weak or whatever, before too long, you see fuzzy light, then it goes all murky, then it's gone and dead. It does whatever you want to call it.
I would call it diffusion.
However, here we have light traveling 13 billion light years, taking 13 billion years to do so, through space, and we see it crystal clear. To me, we should be seeing fuzzy light, not stars and galaxies.
I know that the spaces between the solar systems, and between the galaxies, is clear, super clear of matter, just space dust, which I once read was just a few atoms per (whatever space it said).
Still....13 billion years of travel? It would seems that the light would disperse on it's own, like a flashlight beam. Or that the light would slowly decompose hitting the few atoms here or there in space. 13 billion years is a hell of a long time, and a hell of a long way. I can't even imagine how many miles that would be.
I'm missing something here, maybe the light is so strong from an entire Galaxy, that space dust, even over a vast amount of time, can't weaken it enough. I don't know.
It seems like a miracle that something can travel that far and not weaken enough, so that we can still see it. I know that it red shifts, but that's not visible, I don't think,
thats something scientists measure with their gadgets.
Really, just an awesome thing, this light stuff. Don't want to get all religious in a science thread, but Satan was known as "light bringer", before his fall into the dark side. Must have been a powerful being to control Light itself. Nevermind that if you are an atheist, it sounds goofy I know.
Light comes in waves ... and over the distance the waves change ... so at one point in the universe you can see radiation ... i know off topic ... cool pictures though
Yeah, but Light is a particle and a wave. At least according to PBS specials. Which is the limit of my understanding. I really make no claim to understand it myself.
But either way, to travel over 13 billion years, and still....
looking for a term here. In sync? To not disperse? To remain "lined up" with the other particles or waves that it travels with?
That, over 13 billion years, part of the light behind the light we see in real time, does not catch up with it, and blur it, or that the light itself does not warp in some way is incredible.
It must mean that light is very stable, even over vast amounts of time, and that the space between galaxies is a lot more clear of matter than what I am conceiving.
light travels at a constant speed i think ... after the easter holidays i will ask this proffessor at uni who did his doctorate on optics (light basically)
yeah, it must travel "super constant", with almost no varience, to give a person looking at it 13 billion years away to see it clearly.
On an unrelated note, I wonder what happens to it? Like when it hits the water in the ocean, and refracts, and goes dark after several feet of H20?
Light is just photons I guess. But where do they go? Do they slow down from the speed of light and become matter?
Ask your professor that one, I have no clue myself. The only clue I have, is that is becomes energy, like when light hits a plant, and the green stuff turns it into energy to live. Maybe it becomes heat, and warms the water.
Whidden said this in post #13 : yeah, it must travel "super constant", with almost no varience, to give a person looking at it 13 billion years away to see it clearly.
On an unrelated note, I wonder what happens to it? Like when it hits the water in the ocean, and refracts, and goes dark after several feet of H20?
Light is just photons I guess. But where do they go? Do they slow down from the speed of light and become matter?
Ask your professor that one, I have no clue myself. The only clue I have, is that is becomes energy, like when light hits a plant, and the green stuff turns it into energy to live. Maybe it becomes heat, and warms the water.
Thats called photosinthesis
I think that light reacts differently when in different desities of objects ... so through air it reactes one way, and through water another ... and yet another way through a vaccum ... i think i learnt something about it in high school science
03-11-2004 11:20 AM
