Big Bang+Distance of a New Star

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In summary, astronomers relate the distance of a new star to the age of the Universe because the light we see from that star has been travelling for billions of years, allowing us to see back in time closer to the Big Bang. The Big Bang did not occur at a single point, but rather everywhere in space.
  • #1
Gonçalo
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When astronomers find a new star, say 15 billion light years away, why do they immediately relate that distance with the age of the Universe (the distance to the Big Bang point)?



--->cause if the Universe were like a balloon, and the Earth and the star were in the the surface of that ballon, their distance could be much bigger than the distance of the Earth to the Big Bang point!...
 
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  • #2
Hi, neighbour
It's not possible to localize stars at 15 billion year lights of distance. In fact, is very difficult to localize galaxies at that distance, imagine stars!
Actually is believed that the big bang didn't started in a point, but that started in an infinite extension of spacetime
 
  • #3
Originally posted by Gonçalo
When astronomers find a new star, say 15 billion light years away, why do they immediately relate that distance with the age of the Universe (the distance to the Big Bang point)?

They don't. They usually leave it in terms of redshift. They only try to translate it into a distance when speaking to the media or laymen. (There are different ways of doing that, depending on what you mean by "distance".)

Also, there was no "Big Bang point" or distance to it: the Big Bang occurred everywhere in space.


--->cause if the Universe were like a balloon, and the Earth and the star were in the the surface of that ballon, their distance could be much bigger than the distance of the Earth to the Big Bang point!...

In the balloon analogy, the surface of the balloon is all of space. There is no space "inside" the balloon, and it doesn't make sense to speak of the distance to anything inside the balloon.
 
  • #4
Welcome to Physics Forums!

Both good responses. One more thing to help clarify...

Due to the finite speed of light, the farther away something is, the older the image is (seeing images from the past). So, if you look at a star that is 1000 light years away (about 6 quadrillion miles away), you are seeing an image that is 1000 years old (i.e., how that star looked 1000 years ago).

So, the further the object you see, the further back you see in time...closer and closer to the Big Bang which occurred about 13.7 billion years ago. And as explained above, the Big Bang happened, not at a point in space, but at EVERY point in space.
 

1. What is the Big Bang theory?

The Big Bang theory is a scientific explanation for the origin of the universe. It proposes that the universe began as a singularity, a point of infinite density and temperature, and has been expanding and cooling ever since.

2. How far away is the closest new star?

The distance of a new star can vary greatly depending on the type of star and its location in the universe. The closest new star to Earth is Proxima Centauri, which is about 4.2 light years away.

3. How do scientists measure the distance of a new star?

Scientists use a variety of methods to measure the distance of a new star, including parallax, spectroscopic parallax, and standard candles. These techniques involve measuring the star's position, motion, and brightness to determine its distance from Earth.

4. How does the distance of a new star affect its appearance?

The distance of a new star can greatly affect its appearance to observers on Earth. Stars that are closer appear brighter and larger, while stars that are farther away appear dimmer and smaller. This is due to the inverse square law, which states that the intensity of light decreases as the distance from the source increases.

5. Why is it important to study the distance of new stars?

Studying the distance of new stars is important for understanding the structure and evolution of the universe. By determining the distance of a star, scientists can also calculate its age, size, and other properties, which can provide valuable insights into the processes that govern the formation and behavior of stars.

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