11 Greatest Unanswered Questions of Physics (1 Viewer)

[Kenneth]

The February issue of Discover magazine has this as their cover story (not on their website yet, unfortunately). Here are the questions:

1. What is Dark Matter?

2. What is Dark Energy?

3. How were the heavy elements from Iron to Uranium made?

4. Do neutrinos have mass?

5. Where do ultrahigh-energy particles come from?

6. Is a new theory of light and matter needed to explain what happens at very high energies and temperatures?

7. Are there new states of matter at ultrahigh temperatures and densities?

8. Are protons unstable?

9. What is gravity?

10. Are there additional dimensions?

11. How did the universe begin?

I thought it was interesting since many of these tie into recent off topic threads. Also interesting in that the greatest questions seem to revolve around the beginning and end of the universe, for the most part.

Kenneth

 

[SteveGon]

Interesting stuff. I recently did some reading on these topics. Made my head hurt, but interesting nonetheless!

 

[BrianW]

I thought protons were recently shown not to be unstable.

I'll try to find the source and post back here.

 

[Kevin P]

3. How were the heavy elements from Iron to Uranium made?

They're made in supernova explosions, from what I've heard/read. How? I dunno, I'm just a computah programmuh. Ask a fizzicist.
KJP

 

[Kenneth]

Their question about the heavy elements revolved around the early universe. Here is their quote:

But when fusion creates elements that are heavier than iron, it requires an excess of neutrons. Therefore, astronomers assume that heavier atoms are minted in supernova explosions, where there is a ready supply of neutrons, although the specifics of how this happens are unknown. More recently, some scientists have speculated that at least some of the heaviest elements, such as gold and lead, are formed in even more powerful blasts that occur when two neutron stars --- tiny, burned-out stellar corpses --- collide and collapse into a black hole.

(Discover Magazine, February 2002, p. 40)

Cheers,

Kenneth

 

[Gregory]

I thought the holy grail of phisics is the theory of everthing.

 

[Jack Briggs]

Dark matter is what intrigues me the most. Considering that it makes up the bulk of the Universe, I've wondered about its implications for interstellar travel.

 

[Carlo_M]

Jeez, Jack, I'd hate to tell you what I think about in my spare time...

 

[Kenneth]

"Why is there something, rather than nothing?"

Isn't that a subset of "How did the universe begin?" We could make it "Why did the universe begin?" but I think we have a better shot at "How"
Kenneth

 

[SteveA]

The greatest unanswered questions in physics are the ones that we cannot even ask. Just as a dog does not have the mental capacity to comprehend calculus - or even be aware that it exists, there are certainly phenomena in nature and physics that are beyond our grasp. There are questions - and answers - that are so far beyond our abilities that we can't even conceive of them!

 

[Darren Davis]

10. Are there additional dimensions?

haven't they found up to 10 dimensions? I'd love to read the article when the stuff is available online. Very good post Kenneth

 

[Steve Enemark]

What is Dark Matter?

Shouldn't that question be: IS there Dark Matter? Has there been any direct evidence of its existence? Last I remember it was basically a way to explain the apparent larger-than-possible mass of the universe.

 

[Kenneth]

Here is an exerpt of their Dark Matter material:

All the ordinary matter we can find accounts for only about 4 percent of the universe. We know this by calculating how much mass would be needed to hold galaxies together and cause them to move about the way they do when they gather in large clusters. Another way to weigh the unseen matter is to look at how gravity bends the light from distant objects. Every measure tells astronomers that most of the universe is invisible.

(Discover, February 2002, p. 38)

They then go on to discuss that it cannot be just clouds of dark material because that doesn't fit the models. They suggest that the material might be something completely different (made of Neutrinos for examples).

Kenneth

 

[Chuck C]

10. Are there additional dimensions?

My physics teacher demonstrated something that has stuck with me forever...

He drew on the chalkboard a stick figure. Mr. 2D was his name, and around him were his stick figure, 2D students. He could move up and down, side-to-side, and just plain anywhere in the cartestian coordinate plane. But here comes my physics teacher...he grabs Mr. 2D and pulls him off the chalkboard. Mr. 2D's students look all around, up down, side to side, anywhere on the 2 dimenional plane, but they can't see him. It turns out Mr. 2D entered another dimension, a third dimenison, the one we know and love.

So if someone vanishes into thin air, then you should be rest assured he or she is in another dimension, right?

Seriously, from our perspective, it's easy to account for all three dimensions, but from a dimension to a lesser degree, it's harder to come up with proof of another dimension.

 

[isobel meldar]

Chuck you should read Flatland by Edwin Abbott. i'm sure it was the inspiration for your teacher's demonstration as it was written in 1880. despite essentially being a math and philosophy book it is a very easy read and a very interesting look at the idea of higher dimensions. (also a satire of Victorian England if you're into that kind of thing)

 

[Dave Poehlman]

If I remember from the show Cosmos.. they explained that each dimension expands on an axis that is perpendicular to the previous one.

ie: to go from a 2 dimensional world (x & y axis) to a 3 dimensional one, you need to move perpendicularily to both the x & y axis (z axis). Now, try to imagine a fourth axis that is "perpendicular" to x y and z! That would be the 4th dimension. It's hard to comprehend because our minds and bodies are accustomed to their 3D existence.

Another way to try and think about it, is if you imagine a sphere that encloses a given space. Now, imagine the surface of that sphere curving in the opposite direction, yet, enclosing the same space.... it makes my head spin.

 

[ikiru]

11. How did the universe begin?

I dont know why this is on the list. Science cant answer issues of origin because origin is outside the realm of science. Origins belong in the realm of Philosophy and Religion, not Science.

-ikiru

 

[Joseph Howard]

...because origin is outside the realm of science..

Why would you state this? Why is it outside the realm

of science. I think origins is the the main reason FOR SCIENCE (any science).

Dr. Joe

 

[Kevin P]

11. How did the universe begin?

It all began... with the HORRENDOUS SPACE KABLOOIE!
From the great scientist and philosopher of modern times, Calvin and Hobbes!

 

[ikiru]

Physics is a second order science that is used to explain how things work, never how things came to be. The tools and methodologies used to explain how things work are not suitable for first order events (creation, etc...).

In my post, I was referring to physics. I guess philosophy could be called a science as well.

-ikiru