Velocity and Aging

[Gryeyes]

Originally Posted by Eomer

Travelling faster or even at the speed of light itself is impossible according to our understanding of general (special? fuck if i know the difference) relativity. So it only makes sense that they circumvent time dilation as well.

Dont some particles travel at those speeds? how could it be impossible?

[Fog]

Originally Posted by Gryeyes

Dont some particles travel at those speeds?

No.

Originally Posted by Gryeyes

how could it be impossible?

Since mass increases indefinitely as you approach the speed of light, it would take an infinite amount of energy to accelerate an object of even infinitesimal resting mass to the speed of light.

[Gryeyes]

Originally Posted by Fog

No.

Photons? Neutrinos? Tachyons?

[/quote]Since mass increases indefinitely as you approach the speed of light, it would take an infinite amount of energy to accelerate an object of even infinitesimal resting mass to the speed of light.[/quote]

As you accelerates towards yes. Doesn't count for particles already traveling at that speed.

[Burf]

Originally Posted by Gryeyes

Dont some particles travel at those speeds?

Originally Posted by Fog

No.

Since mass increases indefinitely as you approach the speed of light, it would take an infinite amount of energy to accelerate an object of even infinitesimal resting mass to the speed of light.

Yes.

Photon - What is a photon?

Under the photon theory of light, a photon is a discrete bundle (or quantum) of electromagnetic (or light) energy. Photons are always in motion and, in a vacuum, have a constant speed of light to all observers, at the vacuum speed of light (more commonly just called the speed of light) of c = 2.998 x 108 m/s.

Basic Properties of Photons
According to the photon theory of light, photons . . .

• move at a constant velocity, c = 2.9979 x 108 m/s (i.e. "the speed of light"), in free space
  
• have zero mass and rest energy.
  
• carry energy and momentum, which are also related to the frequency nu and wavelength lamdba of the electromagnetic wave by E = h nu and p = h / lambda.
  
• can be destroyed/created when radiation is absorbed/emitted.
  
• can have particle-like interactions (i.e. collisions) with electrons and other particles, such as in the Compton effect.

More fun:

Special Relativity - an overview of Einstein's theory of special relativity

Speed of Light
No object with mass can accelerate to precisely the speed of light. A massless object, like a photon, can move at the speed of light. (A photon doesn't actually accelerate, though, since it always moves exactly at the speed of light.)
But for a physical object, the speed of light is a limit. The kinetic energy at the speed of light goes to infinity, so it can never be reached by acceleration.

Some have pointed out that an object could in theory move at greater than the speed of light, so long as it did not accelerate to reach that speed. So far no physical entities have ever displayed that property, however.


Much smarter people than us have discussed this stuff. I still recommend the book The Elegant Universe, by the way.

[Fog]

Photons, OK. Neutrinos seem to have mass and do not seem to travel at the speed of light, and nobody has ever seen a tachyon.

Disclaimer: I'm not a physics major, but I have read all the same pop science books and have some physics major friends who enjoy spending a long time explaining things to me.

[RiskyChris]

Originally Posted by Gryeyes

As you accelerates towards yes. Doesn't count for particles already traveling at that speed.

What particles traveling at that speed? Photons?

I don't understand your point.

[Gryeyes]

Originally Posted by RiskyChris

What particles traveling at that speed? Photons?

I don't understand your point.

Traveling towards the speed of light is different than objects that always travel at that speed.

Neutrinos travel at the speed of light (or very very close) but also have some infinitesimal amount of mass.

[RiskyChris]

Originally Posted by Gryeyes

Traveling towards the speed of light is different than objects that always travel at that speed.

Neutrinos travel at the speed of light (or very very close) but also have some infinitesimal amount of mass.

Very very close is actually very very far from the speed of light.

You originally questioned the impossibility of traveling at the speed of light -- this doesn't really change that.

Originally Posted by wiki

According to relativity, if neutrinos are massless, they must travel at the speed of light. However, if they carry a mass, they cannot reach the speed of light.

[Gryeyes]

Originally Posted by RiskyChris

Very very close is actually very very far from the speed of light.

You originally questioned the impossibility of traveling at the speed of light -- this doesn't really change that.

The way they ascribe mass to neutrinos but allow them to travel at near/same speed is very fucking strange and i dont pretend to understand it. Its so close we cannot detect a difference of speed. But they behave in ways that assumes they have mass. The esoteric math that explains it is beyond me.

I dont really have the knowledge to explain how they oscillate between states and alter their mass as they travel. My original question was rhetorical its obvious some things travel at the speed of light.

[Fog]

Originally Posted by Gryeyes

I dont really have the knowledge to explain how they oscillate between states and alter their mass as they travel. My original question was rhetorical its obvious some things travel at the speed of light.

It's sure a long way from obvious. As far as I'm concerned, anything that travels at the speed of light - besides light, as you accurately pointed out - is stretching the definition of a "thing" because it certainly doesn't act much like the normal sort of things you understand and deal with daily.

[Ninajrr]

The upper bound on velocities is misnamed as the Speed of Light, it is more adequately described as the Speed of Information. Light can be described as a particle or as a wave. When referred to as a particle we call it a photon; light (and photons) travel at this speed, but have no mass. Gluons fall into the same category.

It is impossible (according to most modern physicists) to send information faster than this speed. By the conventional definition of a particle, however, it is safe to say that particles can travel at this speed. Still, it is impossible for any particle with mass to achieve such a speed because it would require an infinite amount of energy to accelerate it to the proper speed. This is a result of the relativistic mass idea which Einstein (and others) proposed. Specifically, it states that as mass-carrying particle accelerates its mass increases in such a way that if you take the limit as the mass goes to infinity, you approach c; or more accurately that if you take the limit as the speed goes to c, the mass (energy) requirement diverges.

Just to offer another bit of information: Tachyons are theoretical particles which have imaginary mass. This isn't some strange physical idea so much as a mathematical one. When plugging an imaginary number in for the mass of a particle, the equations which govern that particle, which were brewed to work for real numbers, do silly things. For some reason, some physicists consider this to be interesting; most don't, as it is just the misuse of a formula which we created to work in a specific way with respect to specific variable types.

Edit: As far as I know there is no known, or rather commonly accepted, physical explanation for neutrino oscillations. The probability distributions of a neutrino suggest that its flavor changes, yet it is merely the probability which changes. Saying anything about it beyond that is a bit difficult at this point; really there isn't a lot known about neutrino oscillations.

Edit Edit: LHC Countdown, for those interested/excited. Higggggss!!

[Kolle]

traveling fast could extend your life, actually. i dunno if someone mentioned this already, but since the rest of the planet would be progressing through time faster by comparison, it means their technology advances would continue. you could hop on your rocket for awhile then just come back to earth when it's the year 4 or 5,000. i assume by then they will have conquered aging. so you get to live forever, install a bionic penis, and whatever else it is they have by then. the downside being that humans wipe out one another and you end up being the last one in the universe. aside from the ones aliens have abducted.

[Burf]

Originally Posted by Kolle

traveling fast could extend your life, actually.

Allllllllright. Let's try this again (even though I laughed at most of your post...good funnies).

Someone on earth lives 80 years. They can do 80 years worth of stuff. In that time, let's say that they can read 500 books.

Someone traveling near the speed of light will (to them) still live 80 years and will still only be able to read 500 books.

However, since time (for the person going near the speed of light) is going "slower," when they return from their trip in their rocket ship, the earth will have progressed more than 80 years (as you humorously pointed out, Kolle).

[Kolle]

traveling fast indirectly increases their life span by giving them access to miracle anti-aging drug. if i had the ability to put myself in the future or some alternate time line that would be the first thing i'd do. immunity to death and ailments. and you know there's gonna be sexual upgrades. vibrating, hallucinogenic secretions, etc...

[Eomer]

Originally Posted by Gryeyes

Dont some particles travel at those speeds? how could it be impossible?

Already been explained.

My original question was rhetorical its obvious some things travel at the speed of light.

Your question wasn't all that rhetorical, and it's not obvious that things travel at the speed of light outside photons (light itself) and some pretty exotic particles that we don't fully understand at this point in time. Again, according to how we currently understand how the universe works it's impossible for any "thing" with mass to travel at or even particularly near the speed of light.

That said, it's entirely possible we'll realize in the future that there's ways around this speed limit with deeper understanding of how the laws of physics actually work, but for the time being it's actually pretty "obvious" that no, "things" (as people typically understand them) don't travel at the speed of light.