It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
originally posted by: KrzYma
a reply to: Arbitrageur
When we try to model gravitation on quantum scales we can't discard the infinities through renormalization like we can for the other interactions, so this is a problem when trying to model what happens inside a black hole for example.
is it because gravity is seen as a one way force ?
attraction only and no repulsion ?
originally posted by: KrzYma
a reply to: dragonridr
OK, than it's not the one way force but the one way bending.
No mass ---> flat
mass ---> not flat, curved
nothing as opposite to it
Opisit of gravity would be no gravity.
Think of a photon they exist we know they do yet seem to not have any gravity. At least that we can detect
originally posted by: KrzYma
a reply to: dragonridr
Opisit of gravity would be no gravity.
no.. no gravity is the start point for gravity
0.......1....2....3...4
there is no -1
originally posted by: KrzYma
a reply to: dragonridr
Think of a photon they exist we know they do yet seem to not have any gravity. At least that we can detect
a photon is a mathematical construct, useful but with no counterpart in reality
That's a bit of a misnomer, but that's how Einstein referred to it. It was actually a calculation done by Soldner, before Einstein, based on some incorrect assumptions such as the photon having mass, but Einstein was unaware that Soldner had already done them. So it's a little confusing in words, but the nice thing about the math is that it's pretty clear below and not subject to such ambiguities, which I guess is why physicists prefer math in many cases as a better language to describe what they want to communicate.
originally posted by: KrzYma
a reply to: Arbitrageur
Newtonian field of attraction ??
is this not Gravity ??
The math was apparently a little tricky even for Einstein because he was off by a factor of 2 the first time he tried to calculate the deflection in 1911, but that was 4 years before he published the Theory of General Relativity in 1915, at which time he reviewed his math and found his error and this math shows where the factor of 2 comes from, see the two terms in equation 7, each of which contributes half:
...and the other half... ???
how comes a half and not 1/3 or 2/3 or something in between??
Well he did suggest corpuscles of light, and people after him like Soldner tried to calculate how such corpuscles might behave if they had mass, but we now know they have no significant mass so those Soldner calculations were flawed.
gravity is the curvature of space in Einstein's world
Newton never even suggested what causes gravity, he only describes "the action" and not "the cause"
No. See section 2.3 on nonrenormalizability of gravity.
originally posted by: KrzYma
is it because gravity is seen as a one way force ?
attraction only and no repulsion ?
originally posted by: dragonridr
originally posted by: KrzYma
a reply to: dragonridr
OK, than it's not the one way force but the one way bending.
No mass ---> flat
mass ---> not flat, curved
nothing as opposite to it
Opisit of gravity would be no gravity. Think of a photon they exist we know they do yet seem to not have any gravity. At least that we can detect
originally posted by: Arbitrageur
Unless you need to do precise calculations, 300,000,000 meters per second is easy to remember and pretty close to the speed of light in a vacuum.
originally posted by: John333
i have a couple questions.
what is the speed of light?
how large is the ovservable universe?
how old is our universe?
The observable universe might be something like 93 billion light years in diameter today but of course we can't see all of it today...the further away we look the further back in time we see.
The big bang is thought to have happened about 13.8 billion years ago.
originally posted by: John333
how did matter travel 47billion light years in all directions, in just 13.8 billion years?
originally posted by: Bedlam
originally posted by: John333
how did matter travel 47billion light years in all directions, in just 13.8 billion years?
The space between the matter expanded as well. It's not just matter on a ballistic course. From the matter's POV, it's moving in Einsteinian space, but the metric is expanding as well.
The question you SHOULD ask is, if all the matter was in one relatively small volume to begin with, why didn't the Universe fizzle into a black hole?
originally posted by: dragonridr
a reply to: John333
Couple of misconceptions here first being there is no center of the iniverse. Realize space is expanding everywhere. So when new space is created that space creates more space and so on. But now because space is getting bigger the distance between objects increase. So in your example we could look at a galaxy 13.3 billion (think this is the oldest we've found if I remember correctly) meaning the light traveled that distance to get here. By now that same galaxy is probably closer to 30 billion. If we continue to observe it we will see it move further and further away. But we can never truly see its current position because the time it takes light to get here.
incorrect. We are not aware that the universe has any "center" and there doesn't appear to be any place in the universe we can point to and say "That's where the big bang happened.
originally posted by: John333
so the big bang happened in the center of the universe correct?
Close, but the fact it's observABLE doesn't mean it's been observed. We will be observing more and more of it as we use better telescopes to do it.
and matter spread out in all directions creating a diameter of 93billion light years so far observed. so we've got planets and star systems that are at least 47billion light years from the center(radius).
That is a question many people arrive at sooner or later, where if you combine the logic that "nothing can go faster than light" with "the universe is 13.8 billion years old", then the radius shouldn't be any bigger than 13.8 billion light years. But, that's not the way it works. I can provide a good technical reference on this if you want to read more but it gets into math.
my main question is this.
how did matter travel 47billion light years in all directions, in just 13.8 billion years?
Again displacement via the metric expansion of space is not the same as traveling THROUGH space. The latter is limited to the speed of light, the former is not.
originally posted by: John333
causing matter to travel 3x faster than the speed of light to reach it's current position on the outer fringes of the observable universe?
I think it's time to give you the technical reference, as it gets technical, but the answer to this question can only be simplified so much. If you really want to know, you need to read this:
if so can you explain how it was deduced that empty space is expanding/multiplying itself as it were? is it because the longer you look the more you see?
We use standard general relativity to illustrate and clarify several common misconceptions about the expansion of the Universe. To show the abundance of these misconceptions we cite numerous misleading, or easily misinterpreted, statements in the literature. In the context of the new standard Lambda-CDM cosmology we point out confusions regarding the particle horizon, the event horizon, the ``observable universe'' and the Hubble sphere (distance at which recession velocity = c). We show that we can observe galaxies that have, and always have had, recession velocities greater than the speed of light. We explain why this does not violate special relativity and we link these concepts to observational tests.