How fast is the Universe expanding?

  • Thread starter Thread starter You
  • Start date Start date
Status
Not open for further replies.
You said:
forgive ignorance but what is s-1 Mpc-1 and how does it work. Thankyou…
Click to expand...
It means that all parts of the universe are expanding away from us at a rate of 67 kilometers per second for every megaparsec of distance they are from us.

For example things that are 1 Mpc away from us are receding from us at 67 km/s, things 2 Mpc away are receding at 134 km/s, and so on.

And a parsec is something like three and a quarter lightyears.
 
DianaCC said:
It means that all parts of the universe are expanding away from us at a rate of 67 kilometers per second for every megaparsec of distance they are from us.

For example things that are 1 Mpc away from us are receding from us at 67 km/s, things 2 Mpc away are receding at 134 km/s, and so on.

And a parsec is something like three and a quarter lightyears.
Click to expand...
thats great, I wonder why they didn’t just say that 🙂
 
Hi YOU,

I assume you are a young person with a thirst for knowledge, so here is something to contemplate:

If the edge of the observable universe is 14 billion parsecs from us, how fast is the most distance observable galaxy from us travelling?

Divide 14 billion parsecs by a million parsecs and multiply by 67 km/sec.

Compare your answer to the speed of light = ~300,000 km/sec.

YPPOP
 
yppop said:
Hi YOU,

I assume you are a young person with a thirst for knowledge, so here is something to contemplate:

If the edge of the observable universe is 14 billion parsecs from us, how fast is the most distance observable galaxy from us travelling?

Divide 14 billion parsecs by a million parsecs and multiply by 67 km/sec.

Compare your answer to the speed of light = ~300,000 km/sec.

YPPOP
Click to expand...
hi, well you are speaking to someone who once had difficulty adding 6 and 7, so maths is not my subject. The best I can do for you is hazard a wild guess that the most distant observable galaxy from us is traveling at roughly one third the speed of light. So I’d ask why can’t we see further than the most distant observable galaxy.
 
You said:
hi, well you are speaking to someone who once had difficulty adding 6 and 7, so maths is not my subject. The best I can do for you is hazard a wild guess that the most distant observable galaxy from us is traveling at roughly one third the speed of light. So I’d ask why can’t we see further than the most distant observable galaxy.
Click to expand...
Hi You,
Sorry if I put any uncalled for pressure on you. It was not my intent. What I perceived in your posts so far is that beautiful human trait called wonder. A trait incidentally that is sorely lacking in this forum. It is my observation that the general form of most threads is disputation rather than dialogue. That is why I find it so refreshing to read your inquisitive posts.

Habitual grace is the awe one experiences from the practice of wonder, the study of God’s creation. So when I gave you that little problem in response to your question about the universe’s expansion I envisioned the awe you might have gotten when you realized that the answer is that the farthest galaxy is receding from us at the amazing value of three times the speed of light.

14 billion parsecs divided by 1 million parsecs equals 14,000 times 67 km/sec equal 938,000 km/sec. That is over 3 times the speed of light. Amazing isn’t it?

The age of the universe is about 13.7 billion years. The light we are receiving that left 13.7 years ago is coming from galaxies about 4.2 billion parsecs away which corresponds to a recessional velocity approximately equal to the speed of light. Everything beyond that is receding faster than light can reach us.

This is a gross simplification of what cosmologists estimate. A more accurate assessment takes into account more complex variables such as the curvature of space and comoving distances.

You may want to check out this web site:

curious.astro.cornell.edu/question.php?number=575

YPPOP
 
yppop said:
Hi You,
Sorry if I put any uncalled for pressure on you. It was not my intent. What I perceived in your posts so far is that beautiful human trait called wonder. A trait incidentally that is sorely lacking in this forum. It is my observation that the general form of most threads is disputation rather than dialogue. That is why I find it so refreshing to read your inquisitive posts.

Habitual grace is the awe one experiences from the practice of wonder, the study of God’s creation. So when I gave you that little problem in response to your question about the universe’s expansion I envisioned the awe you might have gotten when you realized that the answer is that the farthest galaxy is receding from us at the amazing value of three times the speed of light.

14 billion parsecs divided by 1 million parsecs equals 14,000 times 67 km/sec equal 938,000 km/sec. That is over 3 times the speed of light. Amazing isn’t it?

The age of the universe is about 13.7 billion years. The light we are receiving that left 13.7 years ago is coming from galaxies about 4.2 billion parsecs away which corresponds to a recessional velocity approximately equal to the speed of light. Everything beyond that is receding faster than light can reach us.

This is a gross simplification of what cosmologists estimate. A more accurate assessment takes into account more complex variables such as the curvature of space and comoving distances.

You may want to check out this web site:

curious.astro.cornell.edu/question.php?number=575

YPPOP
Click to expand...
Look at you go YPPOP! That is awesome to take the time to generate some excitement for math and science in others. (This is not sarcasim. I am really impressed.)
 
But how can something [a galaxy] travel 3 times the speed of light? Thats really fast. If a galaxy has stars from my [fixed] point of view the star cannot emit light because the star passes out its own light at three times lights speed, but from the stars point of view it emits light normally as any other star traveling below the speed of light. :confused:
 
You said:
But how can something [a galaxy] travel 3 times the speed of light? Thats really fast. If a galaxy has stars from my [fixed] point of view the star cannot emit light because the star passes out its own light at three times lights speed, but from the stars point of view it emits light normally as any other star traveling below the speed of light. :confused:
Click to expand...
Hi YOU
When we use the word travel we usually think about an object travelling “through space”. This is not the case in the expansion of the universe, the galaxies are not travelling through space; space is expanding. So just as the distant galaxy is receding from us at three times the speed of light; we also are receding from them at the same speed. Yet we don’t notice that we are moving away at that speed, we don’t notice the speed at all. For example, while you are sitting at your computer you are moving with the rotation of the earth anywhere from 0-1000 mph depending where you are located between the pole and the equator. Also you are moving with the earth around the sun at about 65,000 mph and we are moving with the sun as the galaxy rotates at over 500,000 mph. And yet you feel as though you are standing (sitting) still.

Regarding the emission of light, according to Einstein’s special theory of relativity the velocity of the source does not affect the velocity of the emitted light; it will always be 300,000 Km/sec, and that is the velocity of light coming from that distant galaxy. The only effect the source velocity has on the emitted light is a change in its wavelength, the so-called red-shift.

Then there is the question about what happens to the Lorentz transformations that predict the slowing of time and the shortening of length as the velocity of an object approaches the speed of light. For any speed of an object greater than the speed of light when applied to the Lorenz transform yields an imaginary number. The unsettled question concerning velocities associated with the expanding universe is “in respect to what”? How should we view the special theory regarding these greater than the speed of light situation?

This forum is not the place to do physics, so what is the philosophical view of the results discussed above? How are the ultraluminal speeds handled by cosmologists? I can find no explanations.

Philosophically, in my opinion, the inadequacies, incomprehensiveness, and inaccuracies of scientific explanations call into question the claim that materialists make that science is the only road to the truth about objective reality. The problem science has in getting to the whole truth is the self-imposed limitation concerning the study of matter, without the possibility of a spiritual component, as the only meaningful object of consideration .

I love science; I have two degrees in physics, but I love God more. It is very disturbing to me when materialistic non-believers, including most scientists, wield science as a weapon in a diminishment of God. I do not want to discourage any one from studying science, I merely want to point out that it is merely a ancillary approach to finding the truth of reality.

YPPOP

YPPOP
 
Status
Not open for further replies.
Back
Top