scientists...please....?

Question

i've heard it said that the universe is still expanding.
1: is this true?
2: how do you know this?
3: how FAST is it expanding? (km^3/hr)
4: what is it expanding into?

and to seperate those in the know from alsorans: how much water could you add to the sun to put out the "fire"? (i already know this one. i know it's a LONG answer, but a couple KEY points will do)

please note, this is not homework. i'm a trucker, not a student.

Answer 1

It's interesting how many non-scientists took a stab at answering this question, considering that you asked specifically for answers from scientists.

1. Yes, it is still expanding. Looks like it isn't going to stop any time soon.

2. The physical contents of the universe takes ["contents" is singular] the form of discrete objects (stars and other things). The fact that these objects are all moving away from each other can be verified by measuring the doppler shift of various kinds of electromagnetic waves radiated by different objects. Velocities can be estimated through the doppler effect, in just the same way a doppler radar can measure the speed at which raindrops are moving.

The most famous example of the use of the doppler effect in astronomical measurements is the "red shift."

The rate at which the universe is expanding varies with the distance away from the point of origin. This phenomenon was noticed in the mid-1920s by the famous astronomer Edwin Hubble, for whom the Hubble Telescope is named. The ratio between the distance from the point of origin and the velocity is know as the Hubble Constant.

The value of the Hubble constant was recently measured using--fair enough--the Hubble Telescope. The Hubble Constant appears to be 70 km/sec/megaparsec, with an uncertainty of 10 percent. This means that a galaxy appears to be moving 160,000 miles per hour faster for every 3.3 million light-years away from Earth.

The universe isn't really expanding into a larger space, in the sense that a waffle expands to fill a waffle iron. (Gee, I wonder if there is any waffle mix left in the kitchen. I'm hungry!)

Rather it is expanding in the sense that a crumpled piece of paper starts to "un-crumple." The curves become less tightly curved and the layers less bunched up, but on an infinitely larger and more convoluted scale. Can't think of a better way to put it right now.

And the sun is not on fire, in the conventional sense. It is a vast blob of gasses heated to an incandescent temperature by an internal thermonuclear reaction. The reaction converts ALL matter to energy, and any amount of water you added would just serve as more material for the reaction.

Answer 2

Space itself is expanding, apparently, because the red shifted light from far away objects implies that the light itself has been somehow stretched. It is a little more complex than that, but I will let you check out the article below for further details rather than copy & paste them here.

What is it expanding into? If you knew that, you would win a nobel prize. No one knows.

As for the rate of expansion, I couldn't find a number on the Internet. Sorry.

Pouring water into the sun probably would not make that much difference. The sun is nuclear powered; it does not burn.

Answer 3

OK, I don't know the answers about the universe expanding. It is, and I think we can tell by objects moving away from us. We can see that they are moving away by how long it takes their radiation to arrive here on earth.

But your sun question is amusing. You couldn't put out the "fire" on the sun with water. It's not fire. It's a nuclear reaction. Even if you douse the sun in water, and prevent oxygen from getting to it, the nuclear reaction will continue. The nuclear reaction doesn't require oxygen.

Answer 4

First, you can't evan get close enough to the sun to put water on it. Second, there isn't enough water in the ENTIER universe to put it out. Third, its not fire its nuclear fision. Or a chemical reaction so you can't put it out

And to anwser your other questions:
1 yes it is true
2 astronomers can measure how far away other things are and use it as a refence to a time they measured before.
3 I have no idea
4 space, what do you think ?

Answer 5

1. Yes

2. I've been told by people I trust. (Did you think I'm going to spend 4 or 5 years to understand the details?)

3. A bit less than twice the speed of light
(cosmological recession velocity)

4. It's future self.

Any amount of water you added to the sun would make the fire burn more.

Is it April 1 yet?

Answer 6

The further you look out into space, the more redshift there is in the light coming from the stars. This shows that they are moviing away from us at a faster rate. Recently it has been etermined that the rate of expansion is increasing due to "dark energy"

More water than exists n our solar system.

Answer 7

if i had to guess i would say no only our knowladge of it is expanding and possably the distance between some planets but not space itself or that wich we call nothing.

Answer 8

According to current data, yes it is.

At least two teams have confirmed the data.

http://www.lbl.gov/supernova/

If you look up Saul Perlmutter you will find the pertinent experiments.

One more link:
http://www.astro.ucla.edu/~wright/cosmology_faq.html#CC

Answer 9

to morningfoxnorth, if it is expanding faster than the speed of light, how could you see it?