Creating a FAQ: Questions about the Universe

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In summary, the conversation is about the need for a sticky FAQ thread in the relativity and cosmology forums to address frequently asked questions and avoid repetition. Some of the questions that could be included in the FAQ are about the gravitational pull of moving objects, the increase of mass with speed, the speed limit of the universe, time dilation, the edge and center of the universe, and the use of cosmic background radiation as a reference frame. While there is currently a FAQ thread, it is incomplete and hard to find, and the suggestion is to have a separate sticky FAQ thread for each forum to address this issue.
  • #1
CosmicVoyager
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Greetings,

I see the same questions asked repeatedly (including by myself). It would be great if once a question is answered, it be added to a FAQ. A FAQ for each forum category.

Such questions include:

1) Does an object A moving relative to an object B exert a stronger gravitational pull on object B than if object A were at rest relative to object B?

2) If the answer to question 1 is yes, then the mass of an object increases with speed, correct?

3) If the answer to question 1 is no, then the mass of an object does not increase with speed, correct?

4) If mass does increase with speed, why?

5) If the mass of an object increases with speed, then the energy radiated from a moving object is greater, correct? The light radiated from a moving object is a higher frequency, correct? So the frequency measured would be a combination of that increase and the redshift or blueshift due to relative speed?

5) What makes the speed limit of the universe what it is?

6) Why does time move slower for higher speed objects? That is, why do processes occur slower such as clocks running slower?

7) Does the universe have an edge?

8) Does the universe have a center?

9) Is the universe finite or infinite?

10) Can the cosmic background radiation (CBR) be used as an absolute reference frame? Does the CBR appear blueshifted in one's direction of motion and redshifted in the other direction?

11) It is said that matter curves space. Illustrations show space around objects as a curved grid. This doesn't make sense to me because it has to be curved relative to something. Curved *relative to what*? The illustration shows the grid curved through space, so according to it space would require something else to be curved through.
 
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  • #2
There is a FAQ, but it's just a single thread that's incomplete and much too hard to find. What we need is a sticky FAQ thread at the top of each forum where it's a serious problem that people are asking the same questions over and over. The forums that need it the most are relativity and cosmology. The other forums can probably do without sticky FAQ threads, but these two can't, in my opinion. Every time I open the cosmology forum there's a discussion about the "center of the universe" or "before the big bang", and the relativity forum has many questions that are asked with an annoying frequency: The twin paradox, the photon's point of view, the mass of the photon, the very long rigid stick, Einstein's thought experiment involving a train and two lightning strikes, mistakes caused by not knowing the SR formula for addition of velocities, why can't you reach speed c, does mass increase with speed,... (I could go on).

This thread should probably be in the feedback section.
 
  • #3
I agree that a sticky FAQ would be helpful, but writing one would probably be quite a difficult exercise in consensus-building.

I maintain my own FAQ here: http://www.lightandmatter.com/cgi-bin/meki?physics/faq

When questions come up that are on my list, I just cut and paste.
 

1. What is the universe?

The universe is everything that exists, including all matter, energy, and space. It encompasses all galaxies, stars, planets, and other celestial bodies.

2. How was the universe created?

The most widely accepted explanation is the Big Bang theory, which suggests that the universe began as a singularity and expanded rapidly about 13.8 billion years ago.

3. Is the universe infinite?

The size and nature of the universe is still a topic of debate among scientists. Some theories suggest that the universe is infinite, while others propose that it has a finite size but no boundaries.

4. Are there other universes?

The concept of multiple universes, or the multiverse theory, is a popular topic among scientists. While there is currently no empirical evidence to support the existence of other universes, some theories suggest that they may exist.

5. Will the universe ever end?

There are several theories about the ultimate fate of the universe. Some propose that it will continue expanding indefinitely, while others suggest that it may eventually collapse or experience a "big rip" in which all matter is torn apart.

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