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+--- Thread: Mother Nature / Universe (/showthread.php?tid=5596)
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Mother Nature / Universe - shogun_assassin - 06-25-2015
I read that space can expand faster than speed of light. And since its expansion accelerates, at one point in future, after we all will be gone, possible newly emerged life form won't see old galaxies we can see today because their light won't reach them anymore and they'll have no clue. I used to be depressed by insane ranges far beyond our reach. Now I'm depressed even more.
www.universetoday.com/119068/how-can-space-travel-faster-than-the-speed-of-light/
https://en.wikipedia.org/wiki/Hubble_eXtreme_Deep_Field
![[Image: 688px-Hubble_Extreme_Deep_Field_%28full_...ion%29.png]](https://upload.wikimedia.org/wikipedia/commons/thumb/2/22/Hubble_Extreme_Deep_Field_%28full_resolution%29.png/688px-Hubble_Extreme_Deep_Field_%28full_resolution%29.png)
Anyway, soon we're going to have really close look at Pluto, our little Solar System fella:
http://pluto.jhuapl.edu/
![[Image: loop_final-home.gif]](http://pluto.jhuapl.edu/images/featuredImages/loop_final-home.gif)
James Webb Space Telescope is scheduled to launch in 2018. It'll catch infrared light so we can see stuff beyond dust. I find its deployment plan absolutely amazing and fragile:
That's some wishful thinking!
https://www.nasa.gov/feature/goddard/nasa-simulation-suggests-black-holes-may-make-ideal-dark-matter-labs
Solar System, Universe and Mother Nature in general thread!
RE: Mother Nature / Universe - SPLAT - 06-25-2015
smoke some weed and youll be fine
RE: Mother Nature / Universe - PinkRobot - 06-26-2015
In that first picture I think I can see Lucy in the sky (with diamonds).
RE: Mother Nature / Universe - kojn^ - 06-26-2015
I like pies.
RE: Mother Nature / Universe - Halogene - 06-26-2015
What fascinates me always is that all the black you can see when you look at the sky in the night is actually the universe before its creation, since light travels with less than infinite velocity which again means that it's only black because light from things that possibly are out there has not yet managed to reach us. Ergo looking at the stars is looking at the distant past and where we see nothing we see what the universe looked like before creation.
SURPRISE! IT LOOKS LIKE NOTHING!
RE: Mother Nature / Universe - Justin - 06-26-2015
Most of the Stars you see on the night sky might have collapsed allready but we haven't noticed it yet as it takes many years for light to travel to the Earth from the most distant ones. Black holes can't be seen as they "suck" the light (strong gravity) however can be detected by emiting radiation (X - rays) also by analyzing orbit of the Stars surrounding the black hole! Every galaxy has its own Black Hole in the middle and we "Milky Way" are no exeption for this!
PS; Too bad we can't fully see or comprehend the galaxy we live in as we would have to fly out of it to get full picture of it's structure. But we Can analyze neighbor galaxies and...
Edit: Halogene check this out And go to 13:25 Mabye the blackness isn't exactly nothing.
https://www.youtube.com/watch?v=aNV1Q--R7-A
RE: Mother Nature / Universe - thimo - 06-26-2015
This subject has always fascinated me. Astrophysics and space in general. Good stuff.
Shame, that we are too primitive to go any further than our own backyard at the moment
And furthest reaches of our universe unreachable by linear travel to go and to see.Some interesting read in my opinion: https://en.wikipedia.org/wiki/Kardashev_scale
You lots think it would be possible to reach 2-4 on kardashev scale for human race?
though, the fourth level might be a bit of science fiction aspects in it!
RE: Mother Nature / Universe - Smilecythe - 06-26-2015
Speed of light has always fascinated me. I've always wondered a couple of things:
1. If you stop time and started walking around, would you appear to be invisible to yourself? And would you see an after image of your body from a 3rd person perspective? Since the time has stopped, the photons emitted by your body would stay still. Since there's no flow of time, there shouldn't be a flow of photons coming from your "real time location" to your eyes either, hence you would not be able to perceive yourself and appear invisible.
2. Assuming you could, would you see the beginning of the universe in a reverse-like footage if you traveled outside of our universe faster than the speed of it's expansion and light?
3. Is time travel real? And the reason we have not seen any time travelers is because the universe is moving constantly, people who come back to the past from our future end up in empty space because earth/milkyway in present time hasn't moved to that location yet. Would inventing time travel also require inventing some kind of FTL gimmick?
4. If you can't perceive the duration of time during speed of light (you going from A to B in speed of light apparently would feel like an instant regardless the distance of lightyears). How would time pass during FTL, how would something faster than instant feel like?
RE: Mother Nature / Universe - shogun_assassin - 06-26-2015
Note that even though I find this stuff most fascinating I'm complete layman in this area and chances are I'm talking complete non-sense.
(06-26-2015, 09:40 AM)Smilecythe Wrote: 1. If you stop time and started walking around, would you appear to be invisible to yourself? And would you see an after image of your body from a 3rd person perspective? Since the time has stopped, the photons emitted by your body would stay still. Since there's no flow of time, there shouldn't be a flow of photons coming from your "real time location" to your eyes either, hence you would not be able to perceive yourself and appear invisible.
You could possibly stop time by moving at speed of light. Special relativity says that speed of light is same in every frame. So no matter how fast you move, you'll always experience same speed of light. So if you fixed some frame with earth and with you in rocket moving at speed of light, for earthlings it'd appear that your time has stopped (your event takes infinite amount of time, somehow comes from Lorentz transformation). But for your eyes (frame fixed at your body), the light would still travel the same speed. Sorry, that probably doesn't answer your question. I think it's not doable. You'd also have infinite amount of mass ^^.
By the way, nice experimental confirmation of this stuff is detection of muon particles, which are created in atmosphere from cosmic radiation and are hitting our radars. They have very short life so even if they traveled at speed of light they'd make it just 600 meters. But thanks to time dilation they live longer for our radars =).
https://en.wikipedia.org/wiki/Time_dilation_of_moving_particles#Experiments
---
Talks about FTL Universe expansion too:
RE: Mother Nature / Universe - Smilecythe - 06-26-2015
(06-26-2015, 10:49 AM)shogun_assassin Wrote: You could possibly stop time by moving at speed of light. Special relativity says that speed of light is same in every frame. So no matter how fast you move, you'll always experience same speed of light. So if you fixed some frame with earth and with you in rocket moving at speed of light, for earthlings it'd appear that your time has stopped (your event takes infinite amount of time, somehow comes from Lorentz transformation). But for your eyes (frame fixed at your body), the light would still travel the same speed. Sorry, that probably doesn't answer your question. I think it's not doable. You'd also have infinite amount of mass ^^.Time actually goes faster the faster you move. If you compare between a guy who sits on a train and a guy who walks the same distance, time would feel to pass faster to the guy on the train and the guy walking would experience time going slower, though the differences are below miniscule and not something you would be able to actually notice. If you traveled at the speed of light you would not have time to even react that you had traveled, let alone enjoy the view. How speed of light works in itself is not essential in my mind puzzle, I'm merely trying to imagine what the light (and world around you) would look like if you could just blatantly against any rules of relativity, freeze time and space.
RE: Mother Nature / Universe - SpiKe - 06-26-2015
(06-26-2015, 09:40 AM)Smilecythe Wrote: 4. If you can't perceive the duration of time during speed of light (you going from A to B in speed of light apparently would feel like an instant regardless the distance of lightyears). How would time pass during FTL, how would something faster than instant feel like?
It would feel... backwards.
That would be a time travel into the past.
Well, not exactly, but you can learn more about it here : https://en.wikipedia.org/wiki/Tachyon
Nobody knows if tachyons really exist, they're just hypothetical particles that are supposed to travel FTL.
@thimo: I'm quite pessimistic, I don't think humans will ever reach 1 on Kardashev's scale. We'll probably run out of oil and other resources before reaching it, then there will be a technological regression. But it's just my opinion
RE: Mother Nature / Universe - aa - 06-27-2015
Whenever something like this comes up, all gamers turn into astrophysicists.
Generyaly, I don't believe that travel faster then light is impossible. The fact that light travels no faster doesn't mean that something else can't. At the same time, everything is relative, if you have two particles traveling at the speed of light on opposite directions, the relative speed between them will be 2 light speeds. At the same time, there is absolutely NO stable point in the universe, every thing is in constant motion in relation to other things. Which means, how can there be any absolute velocity in our universe? Which on turn implies that there can't be an absolute speed limit.
Sorry for being so blurry.
And remember, Einstein said something about a person not knowing the rules and breaking them making the important discoveries.
RE: Mother Nature / Universe - SpiKe - 06-27-2015
(06-27-2015, 04:59 PM)aa Wrote: Generyaly, I don't believe that travel faster then light is impossible. The fact that light travels no faster doesn't mean that something else can't. At the same time, everything is relative, if you have two particles traveling at the speed of light on opposite directions, the relative speed between them will be 2 light speeds. At the same time, there is absolutely NO stable point in the universe, every thing is in constant motion in relation to other things. Which means, how can there be any absolute velocity in our universe? Which on turn implies that there can't be an absolute speed limit.
No, the relative speed between 2 particles travelling at the speed of light on opposite directions would be... the speed of light.
Both distance and time are variables, the speed of light is the constant here.
That's why Einstein theories are so mind blowing and complicated.
I don't pretend to understand them myself
RE: Mother Nature / Universe - aa - 06-30-2015
... And I dont even care!!!...
Metallica, Sad But True, Some when in the past.
RE: Mother Nature / Universe - PinkRobot - 06-30-2015
(06-27-2015, 05:20 PM)SpiKe! Wrote: No, the relative speed between 2 particles travelling at the speed of light on opposite directions would be... the speed of light.
Both distance and time are variables, the speed of light is the constant here.
That's why Einstein theories are so mind blowing and complicated.
I don't pretend to understand them myself
I am perfectly fine to accept this as fact, but I don't understand your explanation. If two cars are always at a constant speed of 100 km/h, that speed is constant, sure, but when going in different directions the speed relative to each other would still be 200 km/h.
But I guess that is where the 'real world' and this world split paths and I should not try to picture it at all
RE: Mother Nature / Universe - Smilecythe - 06-30-2015
How speed is relative between passing by objects is not an applicable way of measuring speed. Even if their speeds relative to each other doubles, neither of them are actually going any faster.
RE: Mother Nature / Universe - aa - 06-30-2015
And, yet speed of cars can be easily measured in relation to the road, but in space, all objects remain in constant motion, and the task of finding a stable point in space, nether the less measuring velocity in relation to it is, extremely difficult.
While measuring the speed of a car is easy, it gets more difficult if try to measure the teal speed of an airplane is more difficult, and you still have atmosphere and surface as a reference point, and it gets even more difficult when you leave earth.
RE: Mother Nature / Universe - Smilecythe - 06-30-2015
Just because the path in front of you is in a cosmic roller coaster, doesn't mean that you're straying off of it by an unverifiable velocity. You, the path and things that you take reference from are all riding that roller coaster together.
To get an idea what speed you're going at in space, initially you can use the doppler shifts emitted by the communication signal between you and earth or the light reflected by the surface of your target (assuming you're going for a planet). Even if you don't have a starting point or a target, you're still good to go. As long as you have something to take reference from, you can get both space displacement and time displacement, measuring speed from that is just a matter of division. If space was completely void of matter, it would only then be impossible to measure speed.
RE: Mother Nature / Universe - Pendulla - 06-30-2015
(06-30-2015, 01:50 AM)aa Wrote: ... And I dont even care!!!...
Metallica, Sad But True, Some when in the past.
METALLICA FUCK YEAH!
RE: Mother Nature / Universe - aa - 07-01-2015
'Couse physics!
(06-30-2015, 02:11 PM)Smilecythe Wrote: Just because the path in front of you is in a cosmic roller coaster, doesn't mean that you're straying off of it by an unverifiable velocity. You, the path and things that you take reference from are all riding that roller coaster together.No no, yes, of course you can measure velocity in space.
To get an idea what speed you're going at in space, initially you can use the doppler shifts emitted by the communication signal between you and earth or the light reflected by the surface of your target (assuming you're going for a planet). Even if you don't have a starting point or a target, you're still good to go. As long as you have something to take reference from, you can get both space displacement and time displacement, measuring speed from that is just a matter of division. If space was completely void of matter, it would only then be impossible to measure speed.
Yes, and yet all refernce points are also following some sort of traectories. Every second, the whole of earth makes 29 km on iits orbit around the sun. The sun is believed to travell at 220 km/s around the galactic core. the cycle will go on forever, in progressing through the galaxy, galaxy clusters, quasars, quasar cluster and continuing so on, since the universe is infinte. Very likly, the known uneverse, created by the big bang, is not the only one of its kind, and "big bangs" have happened on multiple occasions (theoreticly infinite amounts of times).
I just have a feeling that the theory of special relativity is just... not right. I hope I am right and eventally i wil prove yall wrong. Maybe get a physical education or something...
RE: Mother Nature / Universe - Pendulla - 07-01-2015
Physical education by kicking your ass. You meant physics education?
RE: Mother Nature / Universe - PinkRobot - 07-01-2015
I miss a poll. Where is the poll.
o Mother Nature
o Universe
RE: Mother Nature / Universe - shogun_assassin - 07-01-2015
(06-30-2015, 02:47 AM)PinkRobot Wrote: I am perfectly fine to accept this as fact, but I don't understand your explanation. If two cars are always at a constant speed of 100 km/h, that speed is constant, sure, but when going in different directions the speed relative to each other would still be 200 km/h.
It can be more intuitive if you note that flow of time and lengths are different for both cars and the observer. I think observer wouldn't measure exactly 200 km/h but I cannot show why...
"We're meaningless and we'll all cease to exist"
"Our crappy brains can't understand the Nature"
I always wondered what causes the (big but no so big) star to explode. More in video description.
What's inside proton? Magic! http://physics.stackexchange.com/a/81194/74520
RE: Mother Nature / Universe - aa - 07-02-2015
(07-01-2015, 11:51 AM)Pendulla Wrote: Physical education by kicking your ass. You meant physics education?
Yeaaa, in this debate the science of sambo is more useful then physics.
RE: Mother Nature / Universe - SpiKe - 07-11-2015
Here's one of the very first high-resolution picture of Pluto + Charon.
The New Horizons space probe is currently over 3 million km from Pluto, but is expected to approach only 12 500 km from the planet the 14th of July.
More beautiful pictures coming