Calgarypuck Forums - The Unofficial Calgary Flames Fan Community

Go Back   Calgarypuck Forums - The Unofficial Calgary Flames Fan Community > Main Forums > The Off Topic Forum
Register Forum Rules FAQ Community Calendar Today's Posts Search

Reply
 
Thread Tools Search this Thread
Old 01-26-2006, 04:46 PM   #61
evman150
#1 Goaltender
 
evman150's Avatar
 
Join Date: Nov 2002
Location: Richmond, BC
Exp:
Default

Quote:
Originally Posted by ken0042
But if it has no mass how come the gravity of a black hole is able to pull it in?
While lacking mass, light still has momentum, energy, and is quantized.

Its momentum (classical momentum is given by p=mv, but there is no mass) is given by the Planck constant divided by the wavelength of the electromagnetic radiation. And light is quantized in what are known as photons. So although light has no mass, it is still subject to the laws of physics, namely gravity.
__________________
"For thousands of years humans were oppressed - as some of us still are - by the notion that the universe is a marionette whose strings are pulled by a god or gods, unseen and inscrutable." - Carl Sagan
Freedom consonant with responsibility.

evman150 is offline   Reply With Quote
Old 01-26-2006, 04:52 PM   #62
ken0042
Playboy Mansion Poolboy
 
ken0042's Avatar
 
Join Date: Apr 2004
Location: Close enough to make a beer run during a TV timeout
Exp:
Default

Cool, thanks evman!
ken0042 is offline   Reply With Quote
Old 01-26-2006, 05:04 PM   #63
Cube Inmate
First Line Centre
 
Join Date: Apr 2004
Location: Boxed-in
Exp:
Default

Ev...that doesn't really sound like a complete answer, because the question still remains, isn't classical gravity a property of matter, with mass? Momentum isn't mass, so why should gravity affect photons?

From my Space.com readings, it sounds like physicists are pretty unanimous that gravity can be adequately described as a curvature of space-time. To me, then, it's pretty intuitive to simply say that light isn't necessarily "attracted" to a mass, but that it simply follows the most direct path through curved space, which happens to be curved by mass.

4-dimensional geometry is confusing.
Cube Inmate is offline   Reply With Quote
Old 01-26-2006, 05:33 PM   #64
evman150
#1 Goaltender
 
evman150's Avatar
 
Join Date: Nov 2002
Location: Richmond, BC
Exp:
Default

Quote:
Originally Posted by Cube Inmate
Ev...that doesn't really sound like a complete answer, because the question still remains, isn't classical gravity a property of matter, with mass? Momentum isn't mass, so why should gravity affect photons?

From my Space.com readings, it sounds like physicists are pretty unanimous that gravity can be adequately described as a curvature of space-time. To me, then, it's pretty intuitive to simply say that light isn't necessarily "attracted" to a mass, but that it simply follows the most direct path through curved space, which happens to be curved by mass.

4-dimensional geometry is confusing.
It's funny cause I was just sitting here thinking that that was a really ****ty answer to the question.

I agree with you, it really wasn't a complete answer. Nothing I said was wrong, but it sort of dances around the question Stephen Harper style.

I'm versed in this stuff, but I'm no expert. Although I really should be.

OK. "But if it has no mass how come the gravity of a black hole is able to pull it in?" Think.

Ok, I gave it a couple minutes of thought. Here's the answer.

It isn't pulled in. It simply can't escape.

You've heard of escape velocity? Like what the NASA guys have to overcome to get out into orbit? It's like that. What does escape velocity depend on? It depends on the mass of the body you're on, and the distance from the centre of that body. The escape velocity of earth is something like 10 km/s, with its small mass. Now imagine trying to escape from the surface of the sun (humour me), it has a mass 200,000 times the earth and 100 times the radius. This results in a surface escape velocity of 620 km/s (by my calculations, you can probably look it up). Now imagine something really massive and with a really small radius. Say an object a million times more massive than the sun with the same radius. What would be the escape velocity of that object? 620,000 km/s. But wait, the speed of light is 300,000 km/s. Nothing can go faster than light. So what happens? No light escapes because it is not going fast enough.

Sorry for the ****ty first answer.
__________________
"For thousands of years humans were oppressed - as some of us still are - by the notion that the universe is a marionette whose strings are pulled by a god or gods, unseen and inscrutable." - Carl Sagan
Freedom consonant with responsibility.

evman150 is offline   Reply With Quote
Old 01-26-2006, 05:34 PM   #65
HOZ
Lifetime Suspension
 
HOZ's Avatar
 
Join Date: Oct 2001
Exp:
Default

Quote:
Originally Posted by Hack&Lube
Can't we just induce artificial gravity, or even stronger than artificial gravity by making part of the ship spin around it's axis to combat atrophe and other obvious problems?
Need to build that ship/station first and have a reactor to keep it spinning.

By solving the gravity problem you open up a whole new can of worms.
HOZ is offline   Reply With Quote
Old 01-26-2006, 05:39 PM   #66
evman150
#1 Goaltender
 
evman150's Avatar
 
Join Date: Nov 2002
Location: Richmond, BC
Exp:
Default

Btw, Cube Inmate is also not wrong. Just like what I first said, what he said is not wrong, it just isn't the answer to your question.

Masses like black holes are not needed to observe light being affected by gravity. Gravitational lensing is commonplace in observational astronomy.

And yes, the popular representation of gravity today is that of a curvature of space. An object's mass results in a "dip" in the fabric of space and anything within the grip of the dip is gravitationally attracted to the central object.
__________________
"For thousands of years humans were oppressed - as some of us still are - by the notion that the universe is a marionette whose strings are pulled by a god or gods, unseen and inscrutable." - Carl Sagan
Freedom consonant with responsibility.

evman150 is offline   Reply With Quote
Old 01-26-2006, 06:03 PM   #67
Patek23
Franchise Player
 
Patek23's Avatar
 
Join Date: Jul 2002
Location: ---
Exp:
Default

Quote:
Originally Posted by Shazam

Let's just hypothesize for a second that modern humans coexisted with Dinosaurs. You do realize the whole argument is a fantasy, seeing as how Dinosaurs in fact did not live at the same time as Humans, right?
Theres a reason for that, The Extinction. Without the larger predators being killed off whatever you want to believe we evolved from wouldn't of had the chance to evovle into us. Homo habilis the earliest of the Homo genus were very short they had roughly 1/3 of the brain capacity of modern day Humans. Homo habilis during their era was the victim of many higher up predators such as sabre tooth tigers, they also had not discovered fire and mainly lived in the dark towards technology the most advanced tool that has been found that co-exists with the era of their discovery is odd shaped rocks that had been used to strike, their survival was maintained by staying in groups while being hunted by a single animal and migrating throughout Africa to avoid predators that would follow.

Now lets think about this, which would you consider more of a predator a 6 meter long 1500 pound raptor with a 9 inch long claw that is used like a dagger or a tiger with exceptionally longer teeth. I'm going to side with the Raptor and then you add in the fact that Raptors hunt in packs I'd say that the Homo habilis would have been wiped out by this immensly superior predator since they were almost wiped out by the inferior sabre tooth tiger (who wasnt even as evovled as the sabretooth tiger that is often referred to in pop culture). Without the Homo habilis surviving there would have been no such thing as Homo sapiens.
Patek23 is offline   Reply With Quote
Old 01-26-2006, 06:07 PM   #68
Patek23
Franchise Player
 
Patek23's Avatar
 
Join Date: Jul 2002
Location: ---
Exp:
Default

Quote:
Originally Posted by troutman
Dinosaurs and remotley Human ancestors never lived on Earth at the same time. Millions of years apart.
I know that, I was saying that if we would have been around at the same time as dinosaurs we would likely of been wiped out or due to dinosaurs surviving longer and our decreased numbers we would have evloved into something completely different. Think if humans were wiped out completely, a couple million years from now do you truly believe that another species wouldn't take the advantage and evovle into a top predator like humans?
Patek23 is offline   Reply With Quote
Old 01-26-2006, 07:00 PM   #69
Hack&Lube
Atomic Nerd
 
Join Date: Jul 2004
Location: Calgary
Exp:
Default

Quote:
Originally Posted by Flaming Homer
I know that, I was saying that if we would have been around at the same time as dinosaurs we would likely of been wiped out or due to dinosaurs surviving longer and our decreased numbers we would have evloved into something completely different. Think if humans were wiped out completely, a couple million years from now do you truly believe that another species wouldn't take the advantage and evovle into a top predator like humans?
But still, humans are not by evolutionary terms, a top predator. Just we evolved the intellect to use tools and organize ourselves and discovered ways to overcome evolutionary shortcomings (low strength, fragile bodies, no bony defenses, no natural weapons) and it turns out we are really good at (and in fact may enjoy) killing things.

I don't really have a problem with your argument that Raptors are pretty lethal creatures, but you keep equating humans with predators.
Hack&Lube is offline   Reply With Quote
Old 01-26-2006, 07:01 PM   #70
Hack&Lube
Atomic Nerd
 
Join Date: Jul 2004
Location: Calgary
Exp:
Default

We can actually travel faster than light if you cheat and slow down light by shining it through a medium like water whose refractive index slows it down

But that's no fun.
Hack&Lube is offline   Reply With Quote
Old 01-26-2006, 07:10 PM   #71
Patek23
Franchise Player
 
Patek23's Avatar
 
Join Date: Jul 2002
Location: ---
Exp:
Default

Quote:
Originally Posted by Hack&Lube
But still, humans are not by evolutionary terms, a top predator. Just we evolved the intellect to use tools and organize ourselves and discovered ways to overcome evolutionary shortcomings (low strength, fragile bodies, no bony defenses, no natural weapons) and it turns out we are really good at (and in fact may enjoy) killing things.

I don't really have a problem with your argument that Raptors are pretty lethal creatures, but you keep equating humans with predators.
I understand that, my point is that all the things you suggest the high intelligence, tools and such were not characteristics in the early Homo genus and that IF the extinction had not occured it would have been extremely (thats using the term lightly as the actual chances are astronomical against us) unlikely that we would survive let alone be as evovled as we are today due to us being pushed down the food web.

Look at it this way if Cows were left alone as a species with small interventions with other creatures chances are high (if evolution is true) that due to that seclusion and them being forced to fend for themselves and out of their element that they would evolve at a higher rate than their surroundings and become the masters of their domain as well as changing immensly in a physical and neurological form. I'm not saying that the cows will be standing up straight and able to speak english fluently as well as aquiring a taste for tea, but a MUCH higher evolved form than they are currently.

Last edited by Patek23; 01-26-2006 at 07:22 PM.
Patek23 is offline   Reply With Quote
Old 01-27-2006, 07:42 AM   #72
Flame On
Franchise Player
 
Flame On's Avatar
 
Join Date: Oct 2002
Exp:
Default

Quote:
Originally Posted by Bring_Back_Shantz
To be fair, the major reason that mamals took over was because the vast majority of the major predators on the planet went extinct at pretty much the same time, there was a void to fill. To say that humans evolved with predators around and to extend that to say we would have even if dinosaurs hand't been wiped out is a little bit of a stretch. Once the dinosaours were gone the pressure was off of mamals and they were able to evolve to fill that void. Without that void, I doubt it wuold have been possible for monkeys to come out of the trees and start hunting mamoths.
I disagree I don't think it's a stretch at all. You make it seem that dinos being extinct was the only obsticle to humans and becuase we didn't have deal with that, well what a cushy ride.
Even if raptors had straight out some unlikely grudge against humans and hunted us, we'd wipe the floor with them. We'd see and understand their hunting tactics and habits because we're smarter. Then we'd use that to our advantage. There isn't an animal alive that humans can't kill with conventional means. Sure there'd be some casualties along the way, but for the most part, over the course of an era, if raptors were to go up against humans, eventually the humans would win. IMO.
Flame On is offline   Reply With Quote
Old 01-27-2006, 07:54 AM   #73
ken0042
Playboy Mansion Poolboy
 
ken0042's Avatar
 
Join Date: Apr 2004
Location: Close enough to make a beer run during a TV timeout
Exp:
Default

Quote:
Originally Posted by Flame On
I disagree I don't think it's a stretch at all. You make it seem that dinos being extinct was the only obsticle to humans and becuase we didn't have deal with that, well what a cushy ride.
It's not the human evolution that most of us are refering to. It's the period from 65 million years ago to 5 million years ago where mammals like rodents eveloved into apes. Those rodents who had to live underground because of those huge dinosaurs were able to move above ground, and into trees where there was food. Eventually they evolved into monkeys and apes, and then from apes into humans.
ken0042 is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 10:55 PM.

Calgary Flames
2024-25




Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright Calgarypuck 2021 | See Our Privacy Policy