Physics question

Recommended Videos

Captain Pancake

New member
May 20, 2009
3,452
0
0
Eukaryote said:
Captain Pancake said:
I'm guessing protons must have some mass if that is the case, however minute. Thus, the only thing with a force strong enough to affect light would be a black hole.
Protons and neutrons account for most of the mass from an element, while electrons are very very very light.

But I think you meant "photons"...
Oh, nuts. Yeah, sorry about that. Photons is what I intended, even I have a comprehensive understanding of something as simple as photons...

*facepalm*

yes, photons must have a negligible, but still present mass.
 

Flames66

New member
Aug 22, 2009
2,310
0
0
There is not a complete understanding of how lingt works. It can be a wave or a particle and its behaviour changes when you are measuring it. So my answer is basically no idea.
 

Cpt_Oblivious

Not Dead Yet
Jan 7, 2009
6,933
0
0
zeldakong64 said:
I've noticed that several people have corrected you so far so you can go ahead and ignore this one. You might consider editing your first post so you don't keep getting messages though
Have done, I've had it before where I find 13 messages correcting me on something where I've admitted I know next to nothing about the subject. All of that was half remembered from TV.
 

effilctar

New member
Jul 24, 2009
1,495
0
0
HardRockSamurai said:
effilctar said:
HardRockSamurai said:
1. We're still not sure if they can.
2. A black hole's gravitational pull is believed to be so strong, it can pretty much suck in anything, except for time (although it's theorized that it can bend time.)
3. Please use Google next time.
Time's a dimension, not a physical entity so it can't be absorbed...
I never said it was.
Am I quoting the wrong man again? Someone mentioned time.
 

Spacewolf

New member
May 21, 2008
1,231
0
0
moose49408 said:
That's kind of a fuzzy area; you're actually hitting on a bit of Einstein's relativity there. To put it short, all gravitational objects affect light, not just black holes. (In fact general relativity was proven by observing that the location of stars shifted from where they should have been when the sun passed in front of them, meaning that the sun's gravity altered the trajectory of the light from those stars) The explanation is a little to complicated to go into here, but here's a link that might help:

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961102.html
ah thank you it isnt that photons have no mass they are just treated the same way electrons are in GCSEs and there mass isnt taken into account unless its dirctly related to the experiment
 

Tzekelkan

New member
Dec 27, 2009
498
0
0
God, I would have thought the sheer amount of nerd per square meter around these parts would mean people who like and/or understand science... guess not.

Apart from the explanation with space bending around a large mass (and what's larger than a black hole, which is most definitely not anti-matter and even if it were, anti matter does not have negative mass!), photons do not have rest mass. That's the mass a body has when it's not moving.

You see, energy and mass are the same thing. When you're not moving, you just have mass, that is rest mass. When you start moving at speed s, you gain energy, that is kinetic energy. And since energy is the same as mass, that means that moving increases your mass (via energy).

So basically jogging makes you fatter.

Well, not really, don't sweat! Since when you stop you lose the kinetic energy, you go back to your rest mass. It's the same with photons, except their rest mass is zero. However, since they move at the speed of light, they actually have quite a bit of energy, which is equivalent to mass through the formula E = mc².
 

LockeDown

New member
Sep 27, 2009
354
0
0
Axioma said:
I'm afraid you're completely and utterly wrong.

As for light, it always travels in a straight line, assuming local spacetime is flat. However, around mass, spacetime is distorted, causing the straight line to become a curve, which is why light bends around heavy objects, such as stars.

The reason why black holes are black is different, however. Any object with a certain mass has an escape velocity. An object's escape velocity is how quickly you need to move off the object's surface to escape its gravity. For planet earth, for an example, the escape velocity is around 11 km/s.

Black holes have an escape velocity greater than the speed of light.
This man here has the correct answer. The nature of all masses is that particles (since light has a dual nature, it still falls under this principle) tend toward objects with mass, because a mass in spacetime bends space itself (and also time, since time is merely another aspect of space, hence the "4th dimension"). This bend distorts the curvature of space, like a peice of paper being bent. And, because all EMR (Electromagnetic radiation) travels in a straight line along the curvature of space, it too is deformed. This occurs with all objects of mass, but the degree of bending scales (I don't remember if it's a slow linear or a true exponential) with respect to the size of the mass in question.

As such, it is possible for an object to be so massive, and thus the curve in spacetime so great, that the path of light traveling sufficiently close to this mass would be distorted to the point that it could no longer escape. These objects, massive singularities theorized to be formed by collapsed stars, are called black holes.

Pardon my wall of text, but as a Physics major, it's so rare that I actually get to use what I'm studying in common discussion. So rare, in fact, that I tend to ramble given the opportunity.
 

Ekonk

New member
Apr 21, 2009
3,120
0
0
Light was both a wave AND a particle, right? I know, it's complete nonsense!

Still, I guess that's why it can be sucked up by a black hole. Because it's also a particle.

Radiation however does escape the black hole's clutches.
 

Canid117

New member
Oct 6, 2009
4,074
0
0
HardRockSamurai said:
1. We're still not sure if they can.
2. A black hole's gravitational pull is believed to be so strong, it can pretty much suck in anything, except for time (although it's theorized that it can bend time.)
3. Please use Google next time.
Gravity is the bending of time and space by the presence of matter. So can a black hole bend time? Yes but so does the toast you eat in the morning.

And @ Ekonk

No actually radiation doesn't escape black holes. (Light is a type of radiation)
The only way to detect a black hole is if there is either something behind it like a gas cloud that makes it obvious or a special trail from gatherings of physical matter (again usually a gas cloud) that identifies it as being there.
 

Tzekelkan

New member
Dec 27, 2009
498
0
0
LockeDown said:
Pardon my wall of text, but as a Physics major, it's so rare that I actually get to use what I'm studying in common discussion. So rare, in fact, that I tend to ramble given the opportunity.
Same.

Ekonk said:
Radiation however does escape the black hole's clutches.
As said before, light is radiation so it's no different. Black Holes are theorized to emit Hawking radiation, but it's a complicated process where a pair of entangled photons spontaneously appear at the event horizon (I think).
 

beddo

New member
Dec 12, 2007
1,589
0
0
Spacewolf said:
My understanding of gravity is that something has to have a mass to be attracted by gravity, and photons have no mass which allows them to travel at the speed of light as they are light (i think). So my question is how do black holes suck in light?
The light or rather photons are not directly affected by gravity. However, the gravity bends space-time. In a black hole's event horizon the space is being stretched inwards so fast that the light does not have enough momentum to overtake it.

It's almost like running up an escalator, your speed remains as you run up it but the ground is moving backwards. If the escalator is too fast or even equal speed to you then you will never make it to the top.
 

beddo

New member
Dec 12, 2007
1,589
0
0
Canid117 said:
HardRockSamurai said:
1. We're still not sure if they can.
2. A black hole's gravitational pull is believed to be so strong, it can pretty much suck in anything, except for time (although it's theorized that it can bend time.)
3. Please use Google next time.
Gravity is the bending of time and space by the presence of matter. So can a black hole bend time? Yes but so does the toast you eat in the morning.

And @ Ekonk

No actually radiation doesn't escape black holes. (Light is a type of radiation)
The only way to detect a black hole is if there is either something behind it like a gas cloud that makes it obvious or a special trail from gatherings of physical matter (again usually a gas cloud) that identifies it as being there.
One way to 'detect' them is to observe the gamma rays from particle collisions that occur as matter tumbles towards the event horizon.
 

beddo

New member
Dec 12, 2007
1,589
0
0
j0z said:
Light is both a particle and a wave, and all particles have mass.
And no, Black Holes are not anti-matter, they are a singularity where the gravity is so strong that light can't even escape. Even our sun bends light around, although it is imperceptible to the naked eye.
A photon is an elementary particle with zero mass.
 

j0z

New member
Apr 23, 2009
1,762
0
0
beddo said:
j0z said:
Light is both a particle and a wave, and all particles have mass.
And no, Black Holes are not anti-matter, they are a singularity where the gravity is so strong that light can't even escape. Even our sun bends light around, although it is imperceptible to the naked eye.
A photon is an elementary particle with zero mass.
It obviously has mass if gravity affects it. Unless my understanding of physics is flawed.
 

Megacherv

Kinect Development Sucks...
Sep 24, 2008
2,650
0
0
Einstein discovered that Energy and Mass are very much related. If a particle starts moving, it gains mass due to its increase in energy. Light has no mass, but it has energy. Light isn't affected when it's in a relavitely weak gravitational field like Earth's. You get to the strength of a black-hole however, and the pull is strong enough to pull you in.

Also, the closer you go to the speed of light, the slower time advances around you. The problem is that nothing can travel at the speed of light except for light (and the rest of the electromagnetic spectrum) because nothing that has mass can travel at the speed of light, as it requires too much energy, which increases the mass. Light is a form that has all its mass in the form of energy.
 

AkJay

New member
Feb 22, 2009
3,555
0
0
Cpt_Oblivious said:
Axioma said:
I'm afraid you're completely and utterly wrong.
TypeSD said:
hURR dURR dERP said:
Black holes are made of superdense matter, not anti-matter.
And that's precisely the reason I said I may be wrong and that I suck at physics.
10BIT said:
You as well.
They correct you because they want to feel smart for once in their lives. They don't even bother reading the rest of your post because they don't want that chance to slip away.
 

008Zulu_v1legacy

New member
Sep 6, 2009
6,019
0
0
Black holes probably don't alter time. The "temporal displacement" we are able to see in the light, when in fact it is the massive gravity altering our perception of objects made visable by said light. Black holes have no greater gravametric pull then a regular star (of the same size as the original), astronomers have found planets in stable orbits around super-dense bodies (Neutron stars and black holes).

As for them sucking in light, I chalk it up to wizards and/or the devil.
 

beddo

New member
Dec 12, 2007
1,589
0
0
j0z said:
beddo said:
j0z said:
Light is both a particle and a wave, and all particles have mass.
And no, Black Holes are not anti-matter, they are a singularity where the gravity is so strong that light can't even escape. Even our sun bends light around, although it is imperceptible to the naked eye.
A photon is an elementary particle with zero mass.
It obviously has mass if gravity affects it. Unless my understanding of physics is flawed.
You're thinking that light is affected by gravity directly but it is not. What is happenning is that the gravity is bending space-time.

From inside the event horizon the light is not travelling fast enough to escape the rate at which space is being stretched by the black hole. Moreover, time is also warped, so what the observer (in the case light) would experience as seconds inside the event horizon would be millennia to us.
 

beddo

New member
Dec 12, 2007
1,589
0
0
008Zulu said:
Black holes probably don't alter time. The "temporal displacement" we are able to see in the light, when in fact it is the massive gravity altering our perception of objects made visable by said light. Black holes have no greater gravametric pull then a regular star (of the same size as the original), astronomers have found planets in stable orbits around super-dense bodies (Neutron stars and black holes).

As for them sucking in light, I chalk it up to wizards and/or the devil.
Black holes bend and stretch space-time to what is essentially its breaking point. Within the event horizon, as you get closer to the singularity time actually slows until it stops.