Extreme distance to the center of our galaxy

senior chef

senior chef

Senior Member
When we look up at the stars, we believe we can witness events that are literally happening right now. However, what we are truly seeing is merely the light from those suns,(to the center of the Milky Way Galaxy) and we are seeing things as they were 28,500 light years ago. How far is that in actual miles ? No way to write it , but it would be a one, followed by hundreds and hundreds of zeros. AND, that is only OUR galaxy. The number of galaxies in the entire universe is also an astronomical number.

Estimated number of planets in the entire universe ? Well, it has been said that that number is greater than the number of grains of sand on ALL the beaches on planet Earth.

What was happening on the Earth 28,500 years ago ? Well, it was aprox the time that Neanderthals became extinct.

We like to think that we have some grasp on time and distance, but our minds simply can not fathom the enormous amounts of time OR distance.
 

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Something that makes my eyes cross is the concept that at one time, there was no such thing as time. And the fact that there's nothing outside of the universe. Not empty space. Just nothing. The universe isn't infinite, but if you get to the edge of it, there's nothing on the other side.

I figure it doesn't do me any good to think about these things, so I don't, except as a transient curiosity when I go, huh. Of course, it's all just theoretical and could all be wrong.
 
Really, can you tell the difference between 5.88 trillion miles, and 4.88 trillion miles. The difference is 1 trillion miles, but it's pretty meaningless. How many trillion-mile bike races have you seen? These numbers are so vast that I don't think we actually comprehend how vast they are.
 
One of the interesting things about the distant galaxies is that we can not know if they still exist. Think about it. Light from some of those galaxies has been traveling for thousands of light years. It is possible that some of those stars/galaxies could have gone super nova and exploded. Hence, some of what we see may not even exist any more. Why ? Because the light from the explosion has not yet reached here.
Some day, an astronomer may be watching a particular star when suddenly it explodes right before his eye.

I enjoy pondering the enormous distances between stars, between galaxies. When I am far away from any man-made light, like high up in the Sierra Nevada Mountains, I occasionally take a blanket out into a mountain meadow, and lie down and watch the stars. I occasionally imagine that I am on another planet and I am looking at our home sun. Then, I think to myself, "Gee, wiz, just look at how far apart Earth is from it's neighbor "star".
 
The "Brick Wall." A long, time ago, when I was younger and very interested in astronomy, I used to wonder where space ended. According to what I learned on earth, there just had to be an ending to space. Well, that is non-sense as space goes on forever. I still can't picture it. Nothing goes on forever here on earth but it seems that in outerspace, space goes on forever and there is no "brick wall" where it ends. Sorry, earth people!
 
Paco Dennis said:
Scientists claim that if an alien 65 million light years away sees earth through a powerful telescope, they can see "dinosaurs". How can that be possible?

https://www.forbes.com/sites/quora/...stars-is-a-look-back-in-time/?sh=165bdd9214ec
Click to expand...
Actually, IMO, that is quite possible. When we see stars, we are seeing them as they appeared light years ago. It takes time for light to travel the enormous distances. Thus, in the hypothetical situation above, an alien would be viewing the light from the earth as it appeared 65 million years ago. HOWEVER, animals do NOT transmit any light. So, the alien could see the Earth, but he could not see any dinosaurs.
 
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@senior chef
A quibble. In message #1 you said "... we are seeing things as they were 28,500 light years ago," and in message #12 you said, "we are seeing them as they appeared light years ago." In both cases, since you are talking about how long ago something was, it should just be "years," which indicates time, not "light years," which indicates distance.

Also in message #12, you said, "... an alien would be viewing the light from the earth as it appeared 65 million years ago. HOWEVER, animals do NOT transmit any light. So, the alien could see the Earth, but he could not see any dinosaurs."

But animals, as well as anything else you can see, do transmit light. If they didn't, you would not be able to see them. Although light which hits them is absorbed, some of the energy is then radiated back into the environment, allowing us to see them. An alien looking at earth through his (its?) extremely powerful telescope would see whatever is on the planet, providing he was looking at a daytime scene.
 
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