LHC

Most of you will of heard of The Large Hadron Collider, a project wich costs around 800 billion dollars. The idea behind this project is to try and find out how our universe was born by recreating conditions just after the Big Bang. The project is truly amazing as is the price tag to run it.

Housing

What i wonder, is how many people could you feed or provide with housing for 800 billion dollars? I would imagine you could help out a whole country or several countries with that kind of money.

CERN

Don't get me wrong i find the CERN project both fascinating and amazing but still it seems weird spending this sort of money on a modern day techno toy. How can we as people accept these kind of projects while we all know that there are plenty of other people in dire need for food and housing?

Check out the following video wich explains what CERN is doing:

Questions and answers

1. Can the lhc will create a dangerous black hole, if not.. why not?

Observational evidence of the universe excludes the possibility that the LHC can create catastrophic black holes which will effect the earth before its natural death when the sun becomes a red giant and envelops the planet billions of years from now.

In layman's terms, "no".

2. Can the LHC will create dangerous strangelets, if not.. why not?

The LHC will not create dangerous strangelets. The RHIC collider at BNL has a higher chance of creating them, and therefore since RHIC has been running quite well for many years with no danger, then there is no chance of the LHC producing dangerous strangelets.

3. Is Hawking Radiation true or just a theory?

We have not yet observed Hawking Radiation, however it is predicted using general principles of quantum mechanics in a curved space-time near a singularity event horizon.

4. Is Hawking Radiation needed to make the LHC safe?

No. While it gives us tremendous confidence in the safety of the machine, a study has been done that relies on nothing but observational evidence and simple physics to demonstrate the safety of the LHC using cosmic rays (which are the same as the LHC hadron-hadron collisions).

5. Is North a spy?

Of course!

Kidding.

6. "Aren't these all just theories with no actual proof that dangerous mBHs won't be created?

No. There are no theories used to demonstrate the safety of the LHC with regards to stable black holes, strangelets, quantum instability, bose-nova explosions, etc.

7. "If there is some probability at all, isn't that too great a risk, no matter how small the chance?"

No. In quantum mechanics, there is a probability that ANYTHING occurs at all, including that you personally create a quantum instability when you turn on your computer and tunnel us all to the middle of the sun, killing the entire planet. The probability is extraordinarily small (much smaller than our comprehension), but still finite. The same is true of the danger of LHC collisions. There is a similarly spectacularly small probability that the LHC will, despite all observational evidence to the contrary, create stable black holes anyway. This is comparably improbable as the chance that the LHC will cause catastrophic damage.

8. "Dr. Roessler says neutron stars are in a special state not susceptible to being gobbled up by black holes. Can you explain why he is incorrect?"

Roessler's arguments are that the core of neutron stars are superfluids, and that superfluids don't interact with fast-moving particles.

Firstly, he hasn't stated why he is correct to begin with. This is simply a statement that he made in a web interview without any support whatsoever.

Secondly, one can very easily demonstrate that superfluids do indeed interact with fast-moving particles, right here on earth.

9. "What about the proposition of Bose novae? Aren't they a danger too?"

No. The superconducting fluid used in the LHC magnets is not capable of undergoing a bose nova.

10. "What are the four forces? I [think I] understand gravity and electomagnetism, but what are these strong and weak interactions?"

The four forces are

1) Gravity.
2) Electromagnetism.
3) The weak interaction.
4) The strong interaction.

Gravity occurs between any two particles with mass (or energy).

Electromagnetism is the force that is mediated by photons (i.e. anything that is electrically charged, or magnetic dipoles, etc).

The strong interaction is the force that holds the nucleus together.

The weak interaction is responsible for radioactive decay. It also turns out that this is the same fundamental force as the electromagnetic interaction, so we now speak of the "electroweak" force.

11. "Why can't anything go faster than light?"

A priori this is not obvious. However we observe that light moves the same in all reference frames. A consequence of this (special relativity) is that nothing can travel faster than the speed of light. The physics community routinely looks for objects moving faster than the speed of light (tachyons), but so far none have been found.

12. "Doesn't a black hole have much more gravity than Earth, and wouldn't creating one immediately destroy the planet?"

No. Black holes can carry any mass whatsoever. The mass of the black holes produced at the LHC (if indeed there are any) will be far less than a proton's mass.

13. Are cosmic ray collisions any different than hadron collider collisions?

Fundamentally, no. They are both hadron-hadron interactions at high energy. This means the physics that governs them is identical in all respects with regard to production of new particles.

The only difference between the two is that collider collisions can be produced at rest with respect to the earth (not always, but a fair fraction), whereas black holes produced with cosmic ray collisions with astronomical bodies are seldom produced at rest***. This means that it is necessary to use objects in the sky for which this larger relativistic velocity with respect to the body in question is not a problem for capturing these black holes. This is why the most stringent limits we have come from neutron stars and white dwarfs, which are massive enough and dense enough to capture any black hole that would potentially cause any danger to earth. We can then place limits on how often such black holes would interact, and based on those numbers we can show that such black holes would not harm the earth in any observable way before the end of the solar system.

*** To determine what this fraction is, specifically, we would need a valid quantum theory of gravity which we do not have.

14. How much energy do cosmic rays have?

A great deal more than the LHC! The highest energy cosmic rays are hypothesized to come form active galactic nuclei, and routinely reach energies several orders of magnitude higher than the LHC center of mass energy.

15. What's the knee?

This comes about from different production mechanisms for cosmic rays in the galaxy and universe as a whole. The highest energy cosmic rays come from galactic nuclei, spewing high energy particles into space. The lower energy cosmic rays can come from a multitude of sources, which are more plentiful. As the energy increases, there are less sources, and so the flux at high energy will be different than that at low energy, resulting in a "knee".

16. Are neutron stars and white dwarfs somehow "immune" to black holes?

No. They are made of matter (or antimatter, it actually doesn't make a difference), carry mass, and therefore will interact with black holes.

17. Is there gravity on the sun and moon?

Yes

18. Is the LHC doing anything different than what has happened in nature?

No. The LHC is merely reproducing conditions that occur all the time in nature, under controlled circumstances so we can study them.

19. Will the LHC create another big bang?

No, because this would have already happened with cosmic rays.

20. Here's my personal pet theory... <snipped>... I don't think you should turn on the LHC until you've disproved it.

There is absolutely no responsibility of any physicist to disprove your pet theory. Physics is a quantitative science. If your personal pet theory carries no predictions, then it is not falsifiable and therefore untestable. This means that there is no reason to take it seriously.

21. Why don't we wait for GLAST?

GLAST will not provide as stringent limits on black hole production at the LHC as observational data of astronomical bodies will. If Hawking radiation is observed at GLAST, there is nothing necessarily (a priori) requiring that all black holes (such as microscopic black holes) will also emit Hawking radiation. In contrast, if we observe astronomical data, we can place much more stringent limits on the possibility that the LHC will produce a dangerous black hole.


22. This doesn't seem useful to do. Why are you not making a better lightbulb or something?

Richard Feynman said it best: "Physics is like sex: sure, it may give some practical results, but that's not why we do it."

We do physics to increase our understanding of the universe. It just so happens that this understanding has invariably led to groundbreaking technological advances, history has told us.

For instance, computers would not be around if, 100+ years ago, scientists didn't start questioning their understanding of how bodies at a certain temperature radiated heat. This seemingly innocuous question paved the way for the quantum mechanical revolution in the 20th century, without which much of our modern society would not exist.

The LHC has the potential for increasing human knowledge about the fundamental structure of space-time and physics immensely. The benefits from this knowledge are unlimited. We simply cannot predict what future generations will do with the knowledge we obtain.

Judging by history, it's a good bet that this increased knowledge will ultimately someday provide tangible benefits. But even if it doesn't, knowledge, in and of itself, is what actually separates us from the other animals on this planet. Without that knowledge, we are nothing but living hand-to-mouth, surviving just about long enough to breed more of ourselves, and not making anything worth living. In short, knowledge is what makes us human to begin with.

The source of the questions and aswers can be found here