the Big Bang?

Question

supposedly the planets are getting farther apart from each other, how do we know that they aint just getting older and fading? for example my teacher showed us these pictures over a 10 year spand of the glaxies are getting farther apart, i argued the statement with this question, how do we know that they are getting farther apart not just getting older and fading, he said because of amount of years there wouldnt have been a noticable difference in the stars age. But I said these Galaxies are thousands to millions of light years away, so over ten earth years these stars could be 10 thousand to 1o million years old or older in just 10 earth years...

(im not very good at wording this sorry)
(im a freshmen)

if the sun is also moving farther away then a few million years ago (im sorry i dont have my paper infront of me that says the amount of millions) it would have been touching earth, according to evolution that the Earth is millions of years old how can this be

Answer 1

They can tell the distance (and that they are moving apart) by examining the shift in the wavelength of the galaxy's light. That is not affected by the light intensity, therefore the age does not enter the equation.

Now, they can tell by the general light waves (and the banding of the light the chemicals produced by the the star or galaxy) to see how old the star is.

Edit: The Earth (and Sun) are BILLIONS of years old (4.5 to be exact). The sun and planets are NOT moving away from each other, unless some force acts on them in the future. Sun has always been, at it's closest point, 91 million miles from Earth.

Where you're confused is that the stars and galaxies, as their own entities, are moving away from each other. The planets and sun are not. We're all moving as a unit.

Answer 2

The intensity of the light from distant galaxies is constant but there is a red shift in the light, which means they are moving away from us. It all has to do with the Doppler effect.

I think you got a bit confused. If a galaxy is 5,000 light years away, it takes light that long to reach us. But, in 10 years time, the light will be still be taking 5,000 years to reach us as the distance that the galaxy will have moved away is very small in terms of light years. Remember a light year is 5,878,625,373,183.61 statute miles. So even if the galaxy was moving away from us at 5 thousand miles an hour it would have traveled 438,000,000 miles away from us in a ten year period or .0075 of a light year, a minuscule fraction which would have no apparent effect on the brightness.

And the planets are not moving away from each other. If anything, it may be that one day the Earth will be drawn into the sun, but not for many billions of years so don't worry about it. For all intents and purposes, the average distance between the planets is constant.

Answer 3

It is true that galaxies are millions of light years away, and that it will take millions of years for their light to reach us. What your teacher was trying to say was that, in 10 years, what we will be seeing of this galaxy will indeed be 10 years older than we observed it 10 years ago. Just because it's far away doesn't mean that it will age differently.
The fact that galaxies are getting further away from eachother is a result of an expanding universe. Think of it this way -- take a deflated balloon and put two dots on it, and measure the distance between the two. It may be as small as a centimeter. But when you blow the balloon up and measure it again, the measurement may increase to the size of a few inches. This is what is happening to our universe.
However, I'm not entirely sure that this is visually observable today, even over a 10 year span. I'm not entirely sure what your teacher is trying to express, but you might be right in questioning it.

Answer 4

The expansion of the Big Bang causes distant galaxies to move apart. Within those galaxies (and within solar systems in those galaxies) there is no expansion. Our solar system is not expanding, the Milky Way is not expanding, the Local Group of galaxies is not expanding, and our local supercluster is not expanding. Beyond that, things are expanding.

The expansion is observable for galaxies that are between 50 million lightyears and several billion lightyears away. We therefore see these galaxies as they were between 50 million years and several billion years ago. They have changed somewhat during that time, but the types of changes are well understood in terms of the known evolution of the stars that make up the galaxies. The galaxies have not faded during that time, on average---mostly, they've gotten bigger and brighter by engulfing smaller galaxies.

The first, main observation of the effect of the Big Bang was observed by E. Hubble. He noticed that more distant galaxies were moving away from us faster than more nearby galaxies.
He could tell the distance to the galaxies by observing standard types of stars inside the galaxies and seeing how bright they were. He could tell the speed of the galaxies by measuring the Doppler shift of the spectral lines of the stars. By plotting galaxy distance against galaxy speed, he found a linear law called the "Hubble relation". The slope of this line is the Hubble constant.

Answer 5

there is no evidence, only theory, the universe could be contracting and we would still be seeing the expansion because ( as im sure you learned )
when you look out into the universe you are looking back in time.
it is impossible to view the expanse of the universe in the present time,
so there are only theories as to what is happening,
Evidence does show an expansion ( not fading ) because of the distances between galaxies have become greater,

P.S. the planets are not getting farther away from each other, all the planets are being pulled into the sun, earth gets a few feet closer to the sun every year ( theoretically )

sounds like your teacher needs to take a refresher course.

Answer 6

The planets are not moving further away from each other... well at least not in a secular way. As planets move in their orbits, the distances between them varies of course but the orbits are pretty much stable and unchanging.

We know galaxies are moving away due to something called red shift. It's like the doppler effect for light. The doppler effect can be noticed in situations such as a train passing by you. As it approaches it sounds one way but when it passes the pitch of the sound is lowered. That is because the oncoming speed of the train adds to the frequency of the sound it emits, but then when it moves away, that outward motion lowers the frequency of the sound it emits.

Light is similar. When objects move very quickly away from us, the light frequency gets shifted into lower wavelengths, red. That is why it is called red shift. We know galaxies are moving away because their light is red shifted.

Answer 7

Theres is something called Red Shift. Look for it on Google or Yahoo search. The best explanation I have heard was picture it as a Fire Truck with it's sirens on. As it speeds closer to you, the sound of the fire truck gets louder. That is the Blue in Red Shift. As it speeds away from you the sound gets fainter and fainter. That is Red Shift. Picture it as Blue being closer and Red being further since B comes before R.

Answer 8

no the big bang is a myth.in a big bang all matter would be moving away from the rest outwardly from one point of origen but you can see evidence of galixy collisions in hubble photos that shows diferent points of galixy origens. you have to by the timeline to so how would a galixy do a 180?

Answer 9

yea