Wow The Universe Is Huge

[Gibsons]

http://harleyk.com/?p=460

 

[McWatt]

We've literally counted at least 2.5 million stars one by one and recorded them in a single catalog (Tycho-2). We also see collections of hundreds of thousands to hundreds of millions of stars in clumps we call clusters or galaxies. In some cases we choose not to catalog each individual star in, say, a cluster because we can't tell much about it due to its low apparent brightness and separation from other luminescent objects, but we can measure the number of stars in a cluster or galaxy quite well using the collection's total brightness.

Yes, we can see other galaxies because extra-galactic space is mostly empty. This is easily proven with a pair of binoculars. You can go out tonight, and barring clouds, see at least one other galaxy. You can also see another few hundred galaxies with a telescope you can set up in your back yard for a few hundred dollars. Having done this myself, I know I'm not being hoodwinked by a giant conspiracy of evil astronomers.

Check out Wikipedia for concise descriptions of thousands of observations we've performed that provide hard evidence for all the things you doubt.

 

[Turtle.Man]

McWatt so asking for definite hard evidence is considered trolling to you? Have we literally counted billions of stars one by one or are we just assuming about the numbers? How is it possible to see other galaxies with telescopes when theres billions of stars between us and them? Explain that one to me or do you think Im still trolling? Im a hardcore skeptic if you dont mind.

Kink:

You're arguing from a very weak position. You ask how it's possible to see things that are hidden behind other objects? Well, you can't (because they're hidden behind other objects). However, we can see things that are NOT hidden by other objects: for example, many stars and galaxies. The vast majority of the observed Universe is (nearly) empty space, which leaves lots of room for light to travel unimpeded.

I encourage you to become familiar with the Hubble Deep Field Survey: in a nutshell, the scope was aimed at a "blank" area of the sky for a couple of weeks for a long exposure photograph. The resulting image showed that the region is richly populated with stars (and galaxies, too!).

t-man

 

[Insomniator]

McWatt so asking for definite hard evidence is considered trolling to you? Have we literally counted billions of stars one by one or are we just assuming about the numbers? How is it possible to see other galaxies with telescopes when theres billions of stars between us and them? Explain that one to me or do you think Im still trolling? Im a hardcore skeptic if you dont mind.

lol wut

This is my first and probably my last post in the HT forums. G'day

 

[Gibsons]

Kink:
--snip--

I encourage you to become familiar with the Hubble Deep Field Survey: in a nutshell, the scope was aimed at a "blank" area of the sky for a couple of weeks for a long exposure photograph. The resulting image showed that the region is richly populated with stars (and galaxies, too!).

t-man

See my link above!

It's got this picture in it

 

[JeffreyLebowski]

It would suck spending 40 years in a space ship and when you reach the destination you find that 50 billion years of technological advancement has already brought about faster-than-light travel, seen the planet colonized, stripped of resources and reduced to a slum world worse than the one you left.

This is what I feel sorry for for the 1st people to leave the solar system. They will be so hyped to be the 1st ones out, but most likely they will be the last ones to reach their destination.

 

[Turtle.Man]

That's the most beautiful patch of empty sky I've ever seen 😀

 

[videogames101]

McWatt so asking for definite hard evidence is considered trolling to you? Have we literally counted billions of stars one by one or are we just assuming about the numbers? How is it possible to see other galaxies with telescopes when theres billions of stars between us and them? Explain that one to me or do you think Im still trolling? Im a hardcore skeptic if you dont mind.

For the same reason you can't see a laser beam, only the points it reflects off of.

Seriously man, you're just derailing the thread.

Have any Von Neumann like devices ever been produced? Out of curiosity.

 

[DisgruntledVirus]

Have any Von Neumann like devices ever been produced? Out of curiosity.

Not that I know of. The closest thing I can think of would be something like a robot making another robot, but that's only if we provide the resources to it. AFAIK nothing has been created which harvests it's own resources to replicate itself.

Although replicators from SG1 would be pretty badass 😛... Minus the whole death/killing thing.

 

[DisgruntledVirus]

BTW that Hubble UDF youtube video was awesome. I'd love to see more like it if anybody has things along those lines.

 

[Hayabusa Rider]

Not that I know of. The closest thing I can think of would be something like a robot making another robot, but that's only if we provide the resources to it. AFAIK nothing has been created which harvests it's own resources to replicate itself.

Although replicators from SG1 would be pretty badass 😛... Minus the whole death/killing thing.

The Replicators would be a von Neumann machine, poorly programmed.

Nothing yet exists that qualifies, but it's just a matter of time. It's an interesting gadget. It could destroy the planet if created by a terrorist once technology reached that level and is an argument against technologically advanced aliens. Considering the age of the universe we should see signs of them everywhere.

 

[A5]

THE NOTION OF MILLIONS OF STARS AND GALAXIES IN OUR UNIVERSE IS ALL A "LIE": TOP ASTRONOMER SAYS

and I totally believe this assumption. He said that if this was true we would be blinded by a white wall of lights from so many light-emitting stars and also blank space in the universe would be white not black.

C'mon it doesn't take a rocket scientist to figure this one out. Go to field in the dark and have 100,000 people with flashlights spaced out around you and shining their flashlights at your face, would you see a white wall or a black wall around you? Would you see another group of 10,000 people beyong that group of 100,000? No you wouldn't, I rest my case.

http://en.wikipedia.org/wiki/Apparent_magnitude

Anything a sufficiently large distance away only radiates a tiny, tiny fraction of it's light in our direction. Take your flashlight example, remove the reflectors from the flashlights, then move the flashlights several miles away and put many of them behind a cloud of dust. That makes it a much better analogy to the actual situation.

The reasoning of your example is why we can't see anything on the other side of the galactic core, though - the density of stars there is just too high to see anything on the other side. The rest of the galaxy's star density is low enough to where we can see between the stars and find others that are more distant.

We can see other galaxies because A) we're relatively near the outer edge of our own galaxy and B) there are far fewer stars on the lines of sight that are perpendicular to the galactic plane - the Milky Way is more of a disk shape, not a sphere.

 

[Mr. Pedantic]

THE NOTION OF MILLIONS OF STARS AND GALAXIES IN OUR UNIVERSE IS ALL A "LIE": TOP ASTRONOMER SAYS

and I totally believe this assumption. He said that if this was true we would be blinded by a white wall of lights from so many light-emitting stars and also blank space in the universe would be white not black.

C'mon it doesn't take a rocket scientist to figure this one out. Go to field in the dark and have 100,000 people with flashlights spaced out around you and shining their flashlights at your face, would you see a white wall or a black wall around you? Would you see another group of 10,000 people beyong that group of 100,000? No you wouldn't, I rest my case.

Look, maybe you should try and (for a change) think before you post.
1) The size and age of the universe is not infinite.
2) The speed of light is not infinite.
3) Energy density decreases proportionally to the square of the distance when emitting in 3 dimensions.
4) Compared to the size of the universe, the amount of fusing matter we can see is really fucking small.
5) The universe isn't divided into glowing things and transparent things.

 

[beginner99]

The Replicators would be a von Neumann machine, poorly programmed.

Nothing yet exists that qualifies, but it's just a matter of time. It's an interesting gadget. It could destroy the planet if created by a terrorist once technology reached that level and is an argument against technologically advanced aliens. Considering the age of the universe we should see signs of them everywhere.

I disagree. Besides the huge dimensions of the universe we have the huge dimension in time which is IMHO even less understandable by human beings. or said other wise to find aliens or replicators you must not only look in the right place you must also look there at the right time.

Even though earth is overpopulated and contains lots of indications of intelligent life (eg. cities) you can't see those from the moon, at least during the day. So even if you look at the right place at the right time (including the fact that you always look into the past) you might still miss what you are looking for.

Even so I believe there have been, are and will be a lot other intelligent lifeforms out there, they will never meet another one, even if such a culture manages to stay stable and develop for thousands of years. The combined space and time factor makes this basically impossible even with very high tech stuff (eg. wormholes).