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#122
Quote by mikeyknowsbetter
I've always wondered about the whole speed of sound/light thing

If the moon was to blow up for example, how long would it be before we saw it had disappeared,, because I assume that it would still be there for a while even after it had blown up?

Also, if an astronaut travelled to the moon, and the returned and looked on the moon with the best telescope ever ever, would he be able to see himself? isn't that time travel?


The moon is about 1 light-second (a little more, but let's not split hairs here :P) away from us, so the delay would be something like a second. The sun, on the other is more like 8 lightminutes away, so if it were to suddenly disappear, we wouldn't notice until 8 minutes later. Speed of light ~300000km/s, distance of sun ~150000000 km, time for light to travel the distance ~150000000km/300000km/s = 500s ~8 min

The second thing you proposed is not possible, since the astronaut would have to go faster than the light in order to reach earth before the light does. That can't happen, look up special relativity. However, when we look at a distant stars 10 lightyears away, we see it in the state it was in 10 years ago, because it took the light 10 years to reach us. Similarly, we can today look out in the microwave range and detect light that is just now reaching us from a time short after the big bang, some 13 point something billion years ago:

http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation


Fascinating stuff!
"In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
Last edited by keinerniemand at Jun 30, 2011,
#123
Quote by fearofthemark
Oh thank god I found this thread. I'm was born April 15 so I'm an Aries right?

what are my inherent Aries traits?


Means you're awesome



stratkat
#124
A good visual representation of the distances between and relative sizes of Earth and the Moon. The yellow beam represents the speed of light traveling between the two. At 300,000km/s light takes 1.26 seconds (sorry to split hairs ) to travel the 380,000km distance (give or take, it varies). Gif from wikipedia.



Quote by fearofthemark
Oh thank god I found this thread. I'm was born April 15 so I'm an Aries right?

what are my inherent Aries traits?


Please dont confuse Astronomy (fact) with Astrology (fiction)
#125
Quote by EuBoat


Means you're awesome


w00t w00t!


Quote by LukeyEL

Please dont confuse Astronomy (fact) with Astrology (fiction)


But my personal horoscope never lies!
Quote by guitarxo
I had a dream about your avatar once, so yes of course.

Quote by Bladez22


every time i see that twirling electrode avatar of yours I know that the post is worth reading or the link is worth clicking


#126
Space always makes me go

The fact that I am seeing something that happened 10 years ago when I look up into the sky and see the stars is so mind****ing. How does that make sense?
pinga
#127
Quote by Cb4rabid
Space always makes me go

The fact that I am seeing something that happened 10 years ago when I look up into the sky and see the stars is so mind****ing. How does that make sense?


Ten years ago? Try ten thousand. Or ten million.
My signature lacks content. It is, however, blue.
#128
Quote by fearofthemark
But my personal horoscope never lies!


Of course it doesn't
#129
Quote by MAC2322
Ten years ago? Try ten thousand. Or ten million.

So im basically watching a recording?
pinga
#131
Quote by Cb4rabid
Space always makes me go

The fact that I am seeing something that happened 10 years ago when I look up into the sky and see the stars is so mind****ing. How does that make sense?


Here's something to think about, when you see the sun 'set', as you see it completely disappear from sight, its actually been out of direct line of sight for almost ten minutes, its just the light is only just making it to us here on Earth.

Our galaxy, the MilkyWay, is about 100,000 light years across. With where we are located in it, if something were to happen at the furthest point from us within the galaxy we wouldn't know about it for about 75,000 years ......

Like big numbers? The MilkyWay is estimated to contain 250 billion stars, one of our neighboring galaxies, Andromeda, is estimated to contain over a TRILLION.

The furthest detected galaxy is 13.5 BILLION light years away, so if we could see it we would be seeing it as it were only a billion years after the big bang.

Its estimated that there is about 170 billion galaxies in the currently observable universe.

All the stars you see in the night sky are only within our own galaxy, bright objects that aren't appearing to twinkle are usually planets within our solar system.

Yes, mind-fornicating indeed
#133
^ There is believed to be, on the lower estimates, 10 septillion stars in the visible universe. That's about as many grains of sand on the Earth.

Lots of other worlds out there, watching back at us perhaps.
#134
Quote by i_am_teh_walrus
^ There is believed to be, on the lower estimates, 10 septillion stars in the visible universe. That's about as many grains of sand on the Earth.

Lots of other worlds out there, watching back at us perhaps.


I do believe there is life out there. The chances of life being possible on a given planet in a given solar system is minuscule, but the number of planets/solar-systems out there is truly staggering so surely it has occurred more than just once (here on Earth).

We have only recently begun detecting planets outside our solar system. And we are no where near detecting planets in other galaxies.

To flat out say life forms on other planets DON'T exist is plane ignorant in my opinion.
#135
Quote by LukeyEL
I do believe there is life out there. The chances of life being possible on a given planet in a given solar system is minuscule, but the number of planets/solar-systems out there is truly staggering so surely it has occurred more than just once (here on Earth).

We have only recently begun detecting planets outside our solar system. And we are no where near detecting planets in other galaxies.

To flat out say life forms on other planets DON'T exist is plane ignorant in my opinion.


The Kepler Telescope surveyed about 1/400th of the night sky, and only about 3000 light years out (a very tiny portion of our galaxy). It discovered nearly 1300 planets, 54 of which were in the habitable zone of their sun, and 5 of which were the size of Earth. Within this one, tiny fraction of our galaxy, there are 5 Earths.

Now human life on Earth has only existed about 200,000 years which is a fraction of a blink in the time scale of the universe, so it would be unreasonable to expect life to exist in our neighboring solar systems in the exact same fraction of a blink that we do. But when we found 5 Earths in this tiny area of this one galaxy (of hundreds of billions), extraterrestrial life starts to seem more like a statistical certainty.
#136
Quote by LukeyEL
Here's something to think about, when you see the sun 'set', as you see it completely disappear from sight, its actually been out of direct line of sight for almost ten minutes, its just the light is only just making it to us here on Earth.



Actually there is a similar effect that occurs because the light from the sun is deflected towards the ground by the atmosphere.

"The ray path of light from the setting Sun is highly distorted near the horizon because of atmospheric refraction, making sunset appear to occur when the Sun’s disk is already about one diameter below the horizon." http://en.wikipedia.org/wiki/Sunset
"In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
#137
Anybody reckon that there might be some kind of life on Titan?
Last edited by conor-figgy at Jul 1, 2011,
#138
Quote by conor-figgy
Anybody reckon that there might be some kind of life on Titan?

I reckon there might be some kind of life anywhere. The question is whether biologists are broad-minded enough about life to see it. I mean hell, you change one base in genetic coding, and HOLY SHIT WE FOUND A TOTALLY BRAND NEW KIND OF LIFE THIS CHANGES ALL OUR DEFINITIONS

It's nearly the same thing........

[IN PHIL WE TRUST]


Quote by Trowzaa
I only play bots. Bots never abandon me. (´・ω・`)

#139
So guys, when is Mars gonna be visible? Or WHERE?I've only recently observed Saturn and Jupiter and honestly it's an incredible experience. You can see the detail so well. However I would like to observe our closest neighbor and according to my charts, Mars is out just before dawn. I just can't find it.
#141
Quote by Cb4rabid
So im basically watching a recording?

No.
It just takes the light that long to get from where it originated to earth.

At the whole life on Titan thing.
It's definitely possible.
I can't think of a reason why it couldn't be possible.
Last edited by darkwolf291 at Jul 1, 2011,
#142
Quote by darkwolf291
No.
It just takes the light that long to get from where it originated to earth.

..........it's not a bad metaphor...

[IN PHIL WE TRUST]


Quote by Trowzaa
I only play bots. Bots never abandon me. (´・ω・`)

#143
Quote by conor-figgy
Anybody reckon that there might be some kind of life on Titan?


I recall seeing an article somewhere about scientists discovering microscopic bacteria on Titan. I could be wrong, but Titan has oceans underneath it's icey surface. The moon is a similar size to the Earth, it wouldn't surprise me if they did find some microscopic organism.


Quote by keinerniemand

The second thing you proposed is not possible, since the astronaut would have to go faster than the light in order to reach earth before the light does. That can't happen, look up special relativity. However, when we look at a distant stars 10 lightyears away, we see it in the state it was in 10 years ago, because it took the light 10 years to reach us. Similarly, we can today look out in the microwave range and detect light that is just now reaching us from a time short after the big bang, some 13 point something billion years ago:



It always fascinates me how you look into the night sky and like, half of what you see doesn't even exist anymore, supernova's and what not.

I remember Brain Cox saying that white noise on the radio is the sound of these mircowaves from the beginning of the universe that have been stretched over time and loss energy.
Last edited by GezzyDiversion at Jul 1, 2011,
#145
Whenever I read this thread and think about how big the universe is and how brief the exist of our planet is compared to the universe, which is only in it's infancy, it just makes me think how pointless things like going to Uni, getting a job and earning money are in this life.
#146
Quote by GezzyDiversion
I recall seeing an article somewhere about scientists discovering microscopic bacteria on Titan. I could be wrong, but Titan has oceans underneath it's icey surface. The moon is a similar size to the Earth, it wouldn't surprise me if they did find some microscopic organism.


Do you mean Europa? Europa is Jupiter's moon which has an icy surface but oceans of liquid water deep below, thanks to the heat that arises from the way the planet is distorted by Jupiter's gravity.

Titan is Saturn's largest moon, and it's remarkable because it has, in a similiar way to how we have a hydrological (water) cycle, a methanological (methane) cycle with oceans of liquid methane. But I don't see why it'd be impossible for some kind of crazy biochemistry to be happening there.

I suspect both of these moons have the highest chances of harbouring some kind of alien life in our solar system

disclaimer: didnt bother researching

Quote by GezzyDiversion
Brain Cox


- - - - - - - -
When I think of the perpetual journey through life
When it always feels like autumn
The wind moves slowly to the north
And the flowers die
Rain falls in my dreams

- - - - - - - -
Last edited by papershredder at Jul 1, 2011,
#148
Quote by papershredder
Titan is Saturn's largest moon, and it's remarkable because it has, in a similiar way to how we have a hydrological (water) cycle, a methanological (methane) cycle with oceans of liquid methane. But I don't see why it'd be impossible for some kind of crazy biochemistry to be happening there.

That's what I was getting at

As far as I know, Titan's atmosphere is too dense for us to see through. Does anyone know if there's a probe being sent soon? - by either NASA or ESA.

EDIT: Just to clarify, not like Cassini but one that'll be sent on a collision course into Titan.

EDIT 2: I'm gonna go read more on Cassini.
Last edited by conor-figgy at Jul 1, 2011,
#149
Quote by conor-figgy
That's what I was getting at

As far as I know, Titan's atmosphere is too dense for us to see through. Does anyone know if there's a probe being sent soon? - by either NASA or ESA.


Cassini-Huygens mission sent a probe that landed on there



Edit: I should add that this picture shows evidence for the methanological cycle because as you can see the stones are rounded and eroded as if by running liquid, scientists have deduced that there was definitely running liquid here.
- - - - - - - -
When I think of the perpetual journey through life
When it always feels like autumn
The wind moves slowly to the north
And the flowers die
Rain falls in my dreams

- - - - - - - -
Last edited by papershredder at Jul 1, 2011,
#150
Cassini - Huygens

While you wait on paper

SHEdit to both edits:

the Huygens probe DID land on Titan.

dat pic: THE ROCKS CLEERLY HAVE BEN SHAPED BY INTELLGENT LIFE. I CALL THIS REAGION BIOSTATION ALFA

[IN PHIL WE TRUST]


Quote by Trowzaa
I only play bots. Bots never abandon me. (´・ω・`)

Last edited by SteveHouse at Jul 1, 2011,
#152
Quote by GezzyDiversion
Whenever I read this thread and think about how big the universe is and how brief the exist of our planet is compared to the universe, which is only in it's infancy, it just makes me think how pointless things like going to Uni, getting a job and earning money are in this life.

Me too man.
We're here for less than a blink of an eye in the universe.
100 years is like a second.
No matter what we do, it will never make a lasting effect on the universe.
We work our 9 to 5 jobs hoping what we do will make an impact on something.
In the end, nothing anyone does matters.
On the other hand, it's kind of a good thing as well.
No matter how much we **** up, it will never effect the universe.
Earth is gonna go away, and once it does, nothing anyone ever did on it will matter.
The Holocaust, Hiroshima, Chernobyl, none of it will matter anymore.
For me, it's a strangely inspirational thought.
#154
Quote by darkwolf291
No.
It just takes the light that long to get from where it originated to earth.

At the whole life on Titan thing.
It's definitely possible.
I can't think of a reason why it couldn't be possible.

But it happened hundreds, possibly thousands of years ago. It's just reaching us now, but it's almost like im watching a recording of what happened x years ago.
pinga
#155
Quote by Twist of fate
Carl Sagan did lots of drugs and because of what he did there's nothing wrong with that.


I don't follow.
#156
Quote by Cb4rabid
But it happened hundreds, possibly thousands of years ago. It's just reaching us now, but it's almost like im watching a recording of what happened x years ago.

To make things easy, yeah, basically.
It just takes the light waves that make that image a long time to get here.
So yeah, in a way, it's like a recording.

Think about this too guys.
Every time you look up into the sky, you're looking back in time.
You're seeing the universe as it was years ago.
#157
Every time you look at anything you're looking back in time >_>



stratkat
#159
Quote by darkwolf291
Me too man.
We're here for less than a blink of an eye in the universe.
100 years is like a second.
No matter what we do, it will never make a lasting effect on the universe.
We work our 9 to 5 jobs hoping what we do will make an impact on something.
In the end, nothing anyone does matters.
On the other hand, it's kind of a good thing as well.
No matter how much we **** up, it will never effect the universe.
Earth is gonna go away, and once it does, nothing anyone ever did on it will matter.
The Holocaust, Hiroshima, Chernobyl, none of it will matter anymore.
For me, it's a strangely inspirational thought.


Well said.

All our 'problems' are insignificant in the scheme of things.

We are powerless to stop the progression of the universe, for example if a nearby star was to become a supernova, the fallout can destroy, or at least catastrophically disturb nearby solar systems (including us) and we couldn't do anything about it

Luckily they are rare, in our timescale anyway. Nothing to worry about in our lifetime.
#160
Quote by darkwolf291
Me too man.
We're here for less than a blink of an eye in the universe.
100 years is like a second.
No matter what we do, it will never make a lasting effect on the universe.
We work our 9 to 5 jobs hoping what we do will make an impact on something.
In the end, nothing anyone does matters.
On the other hand, it's kind of a good thing as well.
No matter how much we **** up, it will never effect the universe.
Earth is gonna go away, and once it does, nothing anyone ever did on it will matter.
The Holocaust, Hiroshima, Chernobyl, none of it will matter anymore.
For me, it's a strangely inspirational thought.


Wrong. Stop being so depressing. Study physics if you really give a shit.