Astronomy & Space Exploration

[BBRBB]

I hate this gravitational waves stuff because I'm too stupid to comprehend it. I understand it's a big deal and proves Einstein's genius even further, but I really don't know what it all means.

Explain it to me like I'm a 10 year old.

Einstein theory states that very heavy objects (we call having a big mass) distort spacetime around them, and it's easy to see that looking on the space very close to the sun is like looking through a lens. A side effect is that in extreme events like two black holes (among the most heavy objects in the universe) orbiting very fast before merging, that distortion of space will be sent around them in what we call gravitational waves travelling at the speed of light.

We detected that with two very long tubes (several kilometers long) placed in different directions, some fancy laser measuring system showing a difference of a tiny fraction of a millimeter between them during a short burst.
Those measured waves correspond exactly to the model of a collision of 2 black holes based on Einstein's equations.

It's fascinating that Einstein predicted that with his pen and paper a century ago while we needed thousands of people working on it, the fastest computers, best technology and spending billions of $ to prove it.

 

[Dr. Dwayne]

I'm intrigued by the notion that gravitational waves can travel at light speed. How does that work?

Not suggesting they are limited to 9.8 m/s as that's an Earth influenced factor but how do they move so quickly in that situation; do they have no mass or is it the distortion of space-time that allows them to do this?

 

[Pexbo]

I'm intrigued by the notion that gravitational waves can travel at light speed. How does that work?

Not suggesting they are limited to 9.8 m/s as that's an Earth influenced factor but how do they move so quickly in that situation; do they have no mass or is it the distortion of space-time that allows them to do this?

It's the whole "no mass" thing isn't it? It's a wave so like sound and light, it's merely passing its energy rather than moving its actual mass. Mass requires energy to move whereas light, sound and now gravitational waves are the energy. That's how I understand it although I'm welcome to be corrected on it.

 

[adexkola]

It's the whole "no mass" thing isn't it? It's a wave so like sound and light, it's merely passing its energy rather than moving its actual mass. Mass requires energy to move whereas light, sound and now gravitational waves are the energy. That's how I understand it although I'm welcome to be corrected on it.

You're spot on.

 

[simonhch]

Wasted all morning reading this thread. But I enjoyed it.

 

[Dr. Dwayne]

It's the whole "no mass" thing isn't it? It's a wave so like sound and light, it's merely passing its energy rather than moving its actual mass. Mass requires energy to move whereas light, sound and now gravitational waves are the energy. That's how I understand it although I'm welcome to be corrected on it.

@Pexbo, chef-cum-astro physicist

Well done fella, cheers.

You're spot on.

@adexkola so does this mean potential new power sources for us or what? Aren't there some hydro dams that utilize gravity indirectly and how could this discovery change the way we look at and harness this force for our benefit?

 

[adexkola]

@Pexbo, chef-cum-astro physicist

Well done fella, cheers.




@adexkola so does this mean potential new power sources for us or what? Aren't there some hydro dams that utilize gravity indirectly and how could this discovery change the way we look at and harness this force for our benefit?

Unfortunately that is beyond our current capabilities, as we don't have a mechanism that can distort gravitational waves in a way that will yield energy, the same way ocean waves crashing against a turbine produces mechanical power. Gravity affects everything on earth. Maybe if we can produce antimatter that would open the door to gravity harnessing devices? But again that's conjecture.

 

[barros]

I'm intrigued by the notion that gravitational waves can travel at light speed. How does that work?

Not suggesting they are limited to 9.8 m/s as that's an Earth influenced factor but how do they move so quickly in that situation; do they have no mass or is it the distortion of space-time that allows them to do this?

and why they aren't attracted to the new black hole.

 

[barros]

I have a question for the guru's here, gravity and time are related so if we go to a planet with gravity 3 times of ours would the time be different? When we look to this image:

We see the squares stretched out so time would be stretched as well, now if a planet with gravity 3* of ours the squares would be even more stretched.

 

[Ubik]

I have a question for the guru's here, gravity and time are related so if we go to a planet with gravity 3 times of ours would the time be different? When we look to this image:

We see the squares stretched out so time would be stretched as well, now if a planet with gravity 3* of ours the squares would be even more stretched.

Very slightly, wouldn't really be noticeable. Takes black-hole level gravity to really mess with time-dilation (as in the film Interstellar, though that's an extreme example).

 

[Invictus]

I have a question for the guru's here, gravity and time are related so if we go to a planet with gravity 3 times of ours would the time be different? When we look to this image:

We see the squares stretched out so time would be stretched as well, now if a planet with gravity 3* of ours the squares would be even more stretched.

Time dilation doesn't just depend on the gravity on said planet, but also on its angular velocity, relative velocity, gravitation potential and 'your' distance from its Schwarzschild radius - r=2Gm/c2 G (which varies from one object to another - and is the radius of that specific object where the escape velocity = c. eg. for an average person - it's about 1.2 x 10^-25 m, for earth - it's about 0.025m, for the Sun - it's 3.0 × 10^3 m) - once you reach that radius, the object becomes a black hole.

In general:
Angular velocity ω = 2π/t ㎭ t^-1.
∆T = √(1-(r^2 ω^2 / c^2))

And, in terms of distance from the event horizon:
T' = T√(1-r/Schwarzschild radius) - The farther away your are from the theoretical 'event horizon' of the body, the faster time will move in relative terms. *

Maybe a few minutes for every century (too small to perceive in noticeable terms), the real crazy stuff only happens in deep gravity wells where the radius of the body ~ its Schwarzschild radius.

* This is why your head is technically older than your feet too - by several billionths of a second.

 

[Mciahel Goodman]

Time dilation doesn't just depend on the gravity on said planet, but also on its angular velocity, relative velocity, gravitation potential and 'your' distance from its Schwarzschild radius - r=2Gm/c2 G (which varies from one object to another - and is the radius of that specific object where the escape velocity = c. eg. for an average person - it's about 1.2 x 10^-25 m, for earth - it's about 0.025m, for the Sun - it's 3.0 × 10^3 m) - once you reach that radius, the object becomes a black hole.

In general:
Angular velocity ω = 2π/t ㎭ t^-1.
∆T = √(1-(r^2 ω^2 / c^2))

And, in terms of distance from the event horizon:
T' = T√(1-r/Schwarzschild radius) - The farther away your are from the theoretical 'event horizon' of the body, the faster time will move in relative terms. *

Maybe a few minutes for every century (too small to perceive in noticeable terms), the real crazy stuff only happens in deep gravity wells where the radius of the body ~ its Schwarzschild radius.

* This is why your head is technically older than your feet too - by several billionths of a second.

I love space travel/astronomy, but the math just goes over my head.

Has anyone ever properly defined the concept of time? I've always assumed that time was tied to motion.

 

[rcoobc]

Maybe a few minutes for every century (too small to perceive in noticeable terms), the real crazy stuff only happens in deep gravity wells where the radius of the body ~ its Schwarzschild radius.

Although humans would never be able to visit such a planet

 

[Invictus]

Although humans would never be able to visit such a planet

Never is a very loaded term though.

No flying machine will ever fly from New York to Paris … [because] no known motor can run at the requisite speed for four days without stopping. It is a bare possibility that a one-man machine without a float and favored by a wind of, say, 15 miles an hour, might succeed in getting across the Atlantic. But such an attempt would be the height of folly. When one comes to increase the size of the craft, the possibility rapidly fades away. This is because of the difficulties of carrying sufficient fuel. It will readily be seen, therefore, why the Atlantic flight is out of the question.

- Orville Wright in 1908, 5 years after Kitty Hawk.

And just 10 years later: http://www.wired.com/2010/06/0615alcock-brown-fly-atlantic/.

Visiting those kind of planets, even neutron stars and black holes, and harnessing that energy might be within the realms of possibility if we survive long enough to reach Level 2+ on the Kardashev scale - though that may be atleast a hundred thousand years from now, if not more.

 

[Rory 7]

This is a great thread. My puny brain is struggling to understand a lot of it but it's still a great thread!

 

[rcoobc]

Never is a very loaded term though.

- Orville Wright in 1908, 5 years after Kitty Hawk.

And just 10 years later: http://www.wired.com/2010/06/0615alcock-brown-fly-atlantic/.

Visiting those kind of planets, even neutron stars and black holes, and harnessing that energy might be within the realms of possibility if we survive long enough to reach Level 2+ on the Kardashev scale - though that may be atleast a hundred thousand years from now, if not more.

Maybe "never" isn't the right term

Maybe it is possible to orbit such a planet and have crazy relativistic effects going on. Actually I don't even know why I said that.

 

[Don't Kill Bill]

Does this measurement of gravity waves show anything about the existence of structure beneath the vacuum, are the waves transmitted through something?

 

[Pexbo]

Does this measurement of gravity waves show anything about the existence of structure beneath the vacuum, are the waves transmitted through something?

There's no such thing as a perfect vacuum, it's already known there is a structure beneath the vacuum else how does light travel through it?

 

[Ubik]

Does this measurement of gravity waves show anything about the existence of structure beneath the vacuum, are the waves transmitted through something?

They're transmitted through spacetime, much as the way planets with mass (see the above picture that barros posted) warp spacetime and produce their gravitational field.

 

[Don't Kill Bill]

There's no such thing as a perfect vacuum, it's already known there is a structure beneath the vacuum else how does light travel through it?

https://en.wikipedia.org/wiki/Luminiferous_aether

Its not like there wasn't a debate with explanations which didn't require a structure. I just wondered if this discovery gives us any information on what the structure is made from, how much does it weigh is it possibly, dark matter, dark energy the Higgs field etc.

 

[barros]

Very slightly, wouldn't really be noticeable. Takes black-hole level gravity to really mess with time-dilation (as in the film Interstellar, though that's an extreme example).

Great movie

 

[barros]

Never is a very loaded term though.

- Orville Wright in 1908, 5 years after Kitty Hawk.

And just 10 years later: http://www.wired.com/2010/06/0615alcock-brown-fly-atlantic/.

Visiting those kind of planets, even neutron stars and black holes, and harnessing that energy might be within the realms of possibility if we survive long enough to reach Level 2+ on the Kardashev scale - though that may be atleast a hundred thousand years from now, if not more.

So we need another war... for some reason all the time we have a war new technology appears.

 

[Raoul]

Time dilation doesn't just depend on the gravity on said planet, but also on its angular velocity, relative velocity, gravitation potential and 'your' distance from its Schwarzschild radius - r=2Gm/c2 G (which varies from one object to another - and is the radius of that specific object where the escape velocity = c. eg. for an average person - it's about 1.2 x 10^-25 m, for earth - it's about 0.025m, for the Sun - it's 3.0 × 10^3 m) - once you reach that radius, the object becomes a black hole.

In general:
Angular velocity ω = 2π/t ㎭ t^-1.
∆T = √(1-(r^2 ω^2 / c^2))

And, in terms of distance from the event horizon:
T' = T√(1-r/Schwarzschild radius) - The farther away your are from the theoretical 'event horizon' of the body, the faster time will move in relative terms. *

Maybe a few minutes for every century (too small to perceive in noticeable terms), the real crazy stuff only happens in deep gravity wells where the radius of the body ~ its Schwarzschild radius.

* This is why your head is technically older than your feet too - by several billionths of a second.

 

[Welsh Wonder]

Invictus knows everything. Not fair.

 

[Shamwow]

Actually the real reason my head is technically older than my feet is because it came out first.

 

[Nick 0208 Ldn]

 

[Invictus]

Sunset on Mars by Curiosity.

What about color? Dust and other fine particles in the atmosphere scatter the blues and greens from the setting or rising Sun to color it yellow, orange and red. When these tints are reflected off clouds, sunset colors are amplified and spread about the sky, making us reach for that camera phone to capture the glory.

Things are a little different on Mars. The ever-present fine dust in the Martian atmosphere absorbs blue light and scatters the warmer colors, coloring the sky well away from the Sun a familiar ruddy hue. At the same time, dust particles in the Sun’s direction scatter blue light forward to create a cool, blue aureole near the setting Sun. If you were standing on Mars, you’d only notice the blue glow when the Sun was near the horizon, the time when its light passes through the greatest depth of atmosphere and dust.

On Earth, blue light from the Sun is scattered by air molecules and spreads around the sky to create a blue canopy. Mars has less the 1% of Earth’s atmosphere, so we only notice the blue when looking through the greatest thickness of the Martian air (and dust) around the time of sunset and sunrise.

http://www.universetoday.com/120353/what-makes-mars-sunsets-different-from-earths/

 

[Nick 0208 Ldn]

 

[Dracula]

Err...did they actually show the sound? I didn't hear anything with the ridiculously over dramatic suspense music in the background

 

[Nick 0208 Ldn]

Err...did they actually show the sound? I didn't hear anything with the ridiculously over dramatic suspense music in the background

From what i recall, there is a piece of audio which begins playing at 2:00 in the first video.

 

[unchanged_lineup]

It's the whistling sound, no? Read some theories that kinda make sense, even though that astronaut at the end says he doesn't buy it. Automatic ramping of gain on the radio straining to get a signal from earth is one, interference within the capsule/between modules in the absence of signals, picking up Jupiter (which "transmits") etc. Many possibles.

 

[BBRBB]

Err...did they actually show the sound? I didn't hear anything with the ridiculously over dramatic suspense music in the background

This trailer like video is really annoying, is everyone supposed to suffer from ADD? You can't even hear the fecking noise cleanly! Put me off watching part 2.

 

[bleedred]

SpaceX trying barge landing of first stage again today with the launch of SES9 satellite.

 

[Nik70]

 

[George Owen]

Are we being swallowed by that yellow stuff?

 

[Pexbo]

Are we being swallowed by that yellow stuff?

That's the Eye of Sauron, it watches rather than swallows.

 

[Nik70]

Are we being swallowed by that yellow stuff?

IC 1011, a galaxy which apparently measures 6 million light years across. The Milky Way comes in at a puny 100 000 light years wide...

 

[unchanged_lineup]

IC 1011, a galaxy which apparently measures 6 million light years across. The Milky Way comes in at a puny 100 000 light years wide...

And yet we think we're the only ones

 

[Invictus]

Are we being swallowed by that yellow stuff?

No. It's ~350 million light-years away from Earth, and not hurtling in our direction. But we will be 'swallowed' by Andromeda in ~3.8 billion years (approaching us at 250,000 mph). Galactic collisions aren't that bad anyway. They'll just merge to become a larger galaxy - since it's mostly empty space.



This is what the sky will look like when that happens.

Shame that we won't be around to see it.

 

[Mrs Smoker]

Just like my wallpaper.