x4rl
Well-known member
Thanks Jo leeching that for later ^_^This is why I love astrophysics! It's utterly awe-inspiring.
Are you watching Brian Cox's latest series "Wonders of the Universe"?
Putting things in perspective
- Thread starter Paul B
- Start date
I bet you won't be sleeping on March 19.ok I really have to stop reading this thread for now - you're stirring up thee passion in me - I'll never get back to sleep!
"On March 19, the moon will swing around Earth more closely than it has in the past 18 years, lighting up the night sky from just 221,567 miles (356,577 kilometers) away. On top of that, it will be full......."
http://news.yahoo.com/s/space/20110310/sc_space/willmarch19supermoontriggernaturaldisasters
Shelley
Well-known member
I watched the wonders of the universe episode 1 the other night. I also enjoyed, and it's well worth watching brian cox other series 5 part "Wonders of the Solar system".
dutchbb
Well-known member
Scientists don't know yet what happened before the big bang, there are only hypotheses about it. The big bang might be a recurring event, part of a bigger cycle, ... There might even be multiple universes (multiverse) which is not unlikely if you think about it.
The big bang created not just matter and energy, it also created time and space. However we can't see all of space, we can only see the light that has travelled back to us. Since the universe is still expanding (and even accelerating in that) its size must be much larger than we can possibly observe. However it's uncertain if it is finite or infinite.
trilogy33
Well-known member
AbsolutelyThis is why I love astrophysics! It's utterly awe-inspiring.
Are you watching Brian Cox's latest series "Wonders of the Universe"?
His previous show: Wonders of the Solar System was pretty awesome too.
Wildcat Media
Well-known member
Have you read the books by his cousins, Matthew Chmod and Martin Chgrp?
Sorry couldn't resist
Jo.
Well-known member
That's a question that would take a lot of explaining, so I'll just give a simplistic reply.
Here's an example of how we know there's Dark Matter as well as ordinary matter... We can measure how fast the stars in a galaxy are moving. The motions of the stars are the result of the gravitational forces of all the other matter in the galaxy. If we add up all the matter from the stars, gas and dust that we can see in that galaxy, it doesn't add up to nearly enough to produce the gravity that cause the motions that we see. This isn't just the case in galaxies, but it happens in galaxy clusters too - if you measure the motions of galaxies within a cluster, the same thing is happening... so there has to be some other form of matter that we can't see, which we call "Dark Matter".
As for Dark Energy... well that's even less understood. The amounts of matter, dark matter and dark energy are based on a model (with observational evidence from experiments like WMAP and SDSS) used to explain why the expansion of the universe is accelerating, rather than slowing down. Dark Energy is the best explanation we have - an energy source so big it could cause the whole universe to expand and strong enough to overcome the gravitational forces between galaxies so as to push them further apart at an accelerating rate.
Cosmology is a huge subject. If you're interested in it, there's a good starter book called "An Introduction to Modern Cosmology" by Andrew Liddle.
Well it's an estimate really - to count them all you have to be able to look deep enough and far back enough to be able to see when galaxies were formed. Estimates are made by counting the number of galaxies in a small area of sky and then using that to estimate how many galaxies there are in the whole sky. In the Hubble Ultra Deep Field, which was taken from what appeared to be a pretty empty area of the sky, there are more than 10,000 galaxies in that field, which covers 11 square arcmins - to put that in more understandable terms, that's like looking at a 1mm x 1mm square of paper from a metre away.
Good old Albert Einstein and his theories ( gravitational lensing) but he did also theorize that space itself as a construct and can expand and contract faster than the speed of light. I thought that the speed of light was only a barrier to things that existed inside of timespace and not the construct of timespace itself. Of course in theory.
OHH OHH We can't forget about axioms quarks quirks gravitons and my favorite tachyons while we are talking about mind bending things here
Yep lol... I was trying to keep it simple. Not that I wouldn't love to get into Special Relativity...
And... yeah the particle physics side of things is just as awesome to think about too! That's why I'm doing my PhD in Astroparticle physics - combines the two! Astrophysics and particle physics at the same time is even more mind blowing.
Jo.
Well-known member
You mean we aren't the center of the universe? I thought we were the biggest thing ever.
Well technically, we are at the centre of our observable universe... but that doesn't mean we are the centre of the universe.
The observable universe would be different for different observers at different positions within the whole universe, and each of those observers would be at the centre of their observable universe. 
EQnoble
Well-known member
Well technically, we are at the centre of our observable universe... but that doesn't mean we are the centre of the universe.
I think my motto/sig fits in nice here ;-)
氣功
Insight is not a matter of intelligence but a sign of point perspective. Without perspective however, prospective intelligence will never have a point.
Jo.
Well-known member
EQnoble
Well-known member
Yay new reading....I would agree with this - it's a very good book.
Actually one of the theories (the multi-verse or omniverse theory which is like a wrapper that includes the laws of matter and physics of all possible iterations of a universe in a multiverse or something to that effect) says that a universe might have slammed for a second into another universe and the release of energy is the big bang it self...and then there is the whole parallel universe levels in theory like bubble theory in level 2 parallel universes. The crazy thing is there isn't that much that we can do to prove or disprove any of them. Good thing that when it comes to existence, the absence of evidence isn't evidence of non-existence
EQnoble
Well-known member
Well the singularity is one thing but we don't know at what point it became unstable...
I probably should have worded it a bit of a different way...when I said a universe slamming into ours, I should have said two universe colliding and transferring energy into what we see as a singularity which spawns a new universe upon expansion. GOOD POINT Dutch.
I probably should have worded it a bit of a different way...when I said a universe slamming into ours, I should have said two universe colliding and transferring energy into what we see as a singularity which spawns a new universe upon expansion. GOOD POINT Dutch.
whynot
Well-known member
Universe can be only ONE... but ...
...Yes,if we think about it,it's possible.
If we think about the religion which says that the Creator created us than we can come up with the idea that another_Creator created Creator.
We are ending up with multiple Creators.
Multiple Creators,multiple Universes...everything is possible if we have the time to think about it.
I think most modern religions would have a problem with the idea of a creator of creators. 'There is no God but Me' is a fairly fundamental tenet.
However, personally I think that to attribute the universe or the multiverse to a creator is to choose a cheap shortcut to understanding where one is not necessary.
However, personally I think that to attribute the universe or the multiverse to a creator is to choose a cheap shortcut to understanding where one is not necessary.
whynot
Well-known member
EQnoble
Well-known member
The problem with that is what if I don't believe in your "creator", that my friend has been the leading cause of death in all of the wars throughout history.