The Planets - TV programme
Discussion
Started watching this the other day, presented by Prof. Brian Cox
Some interesting info in there for a no-knowledge numptie like me but he said a couple of things that puzzled me considering he stated that we "know" so much now about what goes on up there.
1) He just stated something to the effect "when the Sun was created" - No mention of how, just it was.
2) Gravity pulled all the bits of rock, dust ang gas that was floating around the new sun and formed the various planets. - What causes or creates gravity?
Two totally serious questions, can anyone enlighten me in (very) simple terms please?
Some interesting info in there for a no-knowledge numptie like me but he said a couple of things that puzzled me considering he stated that we "know" so much now about what goes on up there.
1) He just stated something to the effect "when the Sun was created" - No mention of how, just it was.
2) Gravity pulled all the bits of rock, dust ang gas that was floating around the new sun and formed the various planets. - What causes or creates gravity?
Two totally serious questions, can anyone enlighten me in (very) simple terms please?
The 2nd question is the easiest. No one really knows. There are 4 fundamental forces of nature. Electromagnetic, strong and weak nuclear force and gravity. The first 3 are pretty well understood. The 4th less so, the interactions between them also are still a mystery.
It's well worth a read of Stephen Hawkins Brief History of Time as that will give a good understanding of a lot of this stuff.
It's well worth a read of Stephen Hawkins Brief History of Time as that will give a good understanding of a lot of this stuff.
According to current theory as I understand it:-
Gravity causes hydrogen floating around to clump together.as it clumps,the hydrogen in the centre gets compressed. As it gets compressed,it heats up. When enough hydrogen clumps together,the centre gets so hot and so densely compressed,it starts fusing together, throwing out loads of light and heat.
A star is born.
Gravity causes hydrogen floating around to clump together.as it clumps,the hydrogen in the centre gets compressed. As it gets compressed,it heats up. When enough hydrogen clumps together,the centre gets so hot and so densely compressed,it starts fusing together, throwing out loads of light and heat.
A star is born.
Eric Mc said:
The universe began 13 billion years ago. The sun was born 4.5 billion years ago - the planets and the rest of the solar system not long after. In a series entitled “The Planets”, they can’t afford to get too bogged down in discusing the birth of the universe itself
Except the OP asks how our Sun was created, not the Universe.Super Sonic said:
According to current theory as I understand it:-
Gravity causes hydrogen floating around to clump together.as it clumps,the hydrogen in the centre gets compressed. As it gets compressed,it heats up. When enough hydrogen clumps together,the centre gets so hot and so densely compressed,it starts fusing together, throwing out loads of light and heat.
A star is born.
This is it ... but the remaining question is "what causes gravity".Gravity causes hydrogen floating around to clump together.as it clumps,the hydrogen in the centre gets compressed. As it gets compressed,it heats up. When enough hydrogen clumps together,the centre gets so hot and so densely compressed,it starts fusing together, throwing out loads of light and heat.
A star is born.
Simply put - we don't really know, and understanding how gravity works is going to be important. To use an analogy - we used to think atoms were billiard balls. At a macro scale, this worked, we could build stuff, burn stuff for energy, life was good. But we could see that at a micro scale, billiard balls didn't really work - so quantum mechanics came about and we have a better (but still not complete) understanding. As a result, we have things like semiconductors, which depend on quantum effects to work.
We are in the same place with gravity. We know that it works - we can model it to the point where we can sling satellites around the solar system with great precision. But we don't know why it works. If we manage to work that out, we may be able to do unexpected things .... which is why it is interesting.
dukeboy749r said:
Except the OP asks how our Sun was created, not the Universe.
I’m surprised the birth of the sun and the formation of the solar system was not covered. I have the original series Cox did called Wonders of the Solar System on DVD and I’m pretty sure that aspect is covered.The way stars are born in gas and dust clouds is now pretty well understood - as we can see stellar birth in action in many places. Some of the detail still needs to be worked out but the general principles are well known.
We are also getting a better handle on how planets are born and how solar systems evolve. The discovery of thousands of other solar systems over the past 30 odd years has increased our knowledge enormously.
Scabutz said:
It's well worth a read of Stephen Hawkins Brief History of Time as that will give a good understanding of a lot of this stuff.
That's quite full on, Bill Bryson's A Short History of Nearly Everything is much more accessible. But both are quite old so not as up to date as they could be.It's a great series, my favourite episode is when they go beyond Saturn, there's a great scale demonstration using Reykjavik harbour (and beyond).
The questions have already been answered, we don't know why gravity happens, it just does, it's proven and can accurately be calculated. Why it seems to be overcome by dark matter and the apparent stretching of space time between the various galaxies etc is another matter, I suppose it's because gravity is actually fairly weak in the grand scheme of things.
Sun formation has already been covered too, hydrogen accumulation in a grand scale to the point where the pressure and resultant temperature are sufficient for fusion to occur, it's thereafter a constant balance between the outward pressure generated by the fusion traction and the inward pressure off gravity that's trying to collapse the star.
The questions have already been answered, we don't know why gravity happens, it just does, it's proven and can accurately be calculated. Why it seems to be overcome by dark matter and the apparent stretching of space time between the various galaxies etc is another matter, I suppose it's because gravity is actually fairly weak in the grand scheme of things.
Sun formation has already been covered too, hydrogen accumulation in a grand scale to the point where the pressure and resultant temperature are sufficient for fusion to occur, it's thereafter a constant balance between the outward pressure generated by the fusion traction and the inward pressure off gravity that's trying to collapse the star.
This week's programme on Jupiter was very interesting. First of all it it spiralled in towards the Sun, gathering up all the debris in the region that would have threatened the Earth & then Saturn formed from debris further out & pulled Jupiter back out again so the Earth could survive in the Goldilocks zone. It seems that most other systems don't have small, water bearing planets close to their suns as they all got hoovered up by the bigger planets spiralling in. Bigger planets = massive gravity.
Now Jupiter acts to pull the solar detritus away from the orbit of the Earth, well at least most of it. One day one big one will get through & that will be game over for us.
When you think of the incredible number of factors that have to be just right for life to form on the Earth it does make you wonder if we are unique in the Universe. The Drake Equation is just a guess, after all.
Now Jupiter acts to pull the solar detritus away from the orbit of the Earth, well at least most of it. One day one big one will get through & that will be game over for us.
When you think of the incredible number of factors that have to be just right for life to form on the Earth it does make you wonder if we are unique in the Universe. The Drake Equation is just a guess, after all.
Super Sonic said:
Regarding gravity, I did see a program about this once presented by prof Jim Al Khalili and they came to a tentative conclusion that gravity was caused by objects (mass) moving towards the location where time moves slowest in it's frame of reference.
Can you remember what it was you saw ?Stan the Bat said:
Super Sonic said:
Regarding gravity, I did see a program about this once presented by prof Jim Al Khalili and they came to a tentative conclusion that gravity was caused by objects (mass) moving towards the location where time moves slowest in it's frame of reference.
Can you remember what it was you saw ?'Gravity and Me: The Force That Shapes Our Lives'
ETA, original release 28/3/17 bbc4
Edited by Super Sonic on Saturday 7th August 19:08
Super Sonic said:
Stan the Bat said:
Super Sonic said:
Regarding gravity, I did see a program about this once presented by prof Jim Al Khalili and they came to a tentative conclusion that gravity was caused by objects (mass) moving towards the location where time moves slowest in it's frame of reference.
Can you remember what it was you saw ?'Gravity and Me: The Force That Shapes Our Lives'
ETA, original release 28/3/17 bbc4
Edited by Super Sonic on Saturday 7th August 19:08
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