# Is there a definite number of atoms in the universe?

• Geekchick
In summary, the number of atoms in the universe is not fixed, as new atoms can be created through various processes. The big bang theory explains the creation of the universe and how energy converted into matter. While the universe is expanding, gravity and other forces hold smaller structures together, preventing everything from being pulled further apart.
Geekchick
This may be a silly question but it just popped into my head yesterday. Are there a definite number of atoms in the universe? Because if the universe is expanding, then does that mean that there are more atoms in the universe or is everything just being pulled farther apart? (however, that logic really does not make sense because as things move apart then something else moves into taking up the newly empty space) If, however, there are more atoms then where could they possibly be coming from? Does this just lead back to how was the universe was created in the first place?

Space news on Phys.org
The big bang model is that pretty much everything was created at the start.
It took a while for the universe to expand and cool enough that energy could convert into matter and then it took a bit longer for atoms to form from other particles.

So in general the amount of mass+energy is fixed. Of course atoms aren't indivisible so for example new helium atoms are being created from hydrogen atoms in the sun, which since it takes 2hydrogen atoms to make one helium means the total number of atoms in the sun is slightly decreasing. Other processes are splitting atoms apart.

As to the expansion of the universe. Although space is expanding, gravity (and other sub-atomic forces) holds things together. So on a very large scale things are moved apart, but gravity keeps anything smaller than galaxies together.

## 1. What is the estimated number of atoms in the universe?

The estimated number of atoms in the observable universe is around 1078, which is a huge number that is difficult to comprehend.

## 2. Can we accurately count the number of atoms in the universe?

No, it is impossible to accurately count the number of atoms in the universe due to the vastness and complexity of the universe. Scientists can only estimate based on various mathematical and observational techniques.

## 3. Are all atoms in the universe different?

No, all atoms in the universe are not different. The periodic table of elements contains all the different types of atoms that exist, and they are made up of the same basic components - protons, neutrons, and electrons.

## 4. Does the number of atoms in the universe change over time?

The number of atoms in the universe remains relatively constant. While atoms can be created or destroyed through nuclear reactions, the total number of atoms in the universe remains approximately the same.

## 5. Is there a possibility that the universe contains an infinite number of atoms?

There is no evidence to suggest that the universe contains an infinite number of atoms. The current understanding of the universe suggests that it has a finite size and therefore a finite number of atoms.

### Similar threads

• Cosmology
Replies
11
Views
2K
• Cosmology
Replies
3
Views
2K
• Cosmology
Replies
32
Views
3K
• Cosmology
Replies
5
Views
1K
• Astronomy and Astrophysics
Replies
4
Views
495
• Cosmology
Replies
13
Views
3K
• Cosmology
Replies
5
Views
2K
• Cosmology
Replies
38
Views
5K
• Cosmology
Replies
16
Views
2K
• Cosmology
Replies
4
Views
2K