38 replies to this topic

[the L]

Well, I admit ignorance about Astronomy. I have some basic knowledge from school and few documentraries but I have more questions opened. Where do I start? Hm..

1. How moon have size exactly to cover sun during solar eclipse?
2. I heard that Jupiter is sun that failed. So is it possible that Jupiter once was Sun or that in future becomes one? Whats the reason why didnt become sun?
3. What makes Hydrogen to fuse into Hellium in our sun?
4. Is just for curiousity. Who was the greater Kepler or Copernicus?
5. Is there any study to show effect of cosmic rays on our body, nature or similar?

Thanks in advance.

[Ryu]

the L, on 26 August 2011 - 08:34 PM, said:

Well, I admit ignorance about Astronomy. I have some basic knowledge from school and few documentraries but I have more questions opened. Where do I start? Hm..

1. How moon have size exactly to cover sun during solar eclipse?
2. I heard that Jupiter is sun that failed. So is it possible that Jupiter once was Sun or that in future becomes one? Whats the reason why didnt become sun?
3. What makes Hydrogen to fuse into Hellium in our sun?
4. Is just for curiousity. Who was the greater Kepler or Copernicus?
5. Is there any study to show effect of cosmic rays on our body, nature or similar?

Thanks in advance.

Hi "the L"

I can answer the first one pretty much. The moon is far closer to us than the sun so when it is in proper position, it moves in front of the sun, obscuring it from our point of view. HOWEVER..depending on where you are, some people will see a total eclipse while in other countries they may only have a partial eclipse.

As for the two gas giants..it is a popular theory that they were failed suns and the core merely became more dense. To be honest I am really unsure however these two planets are by far the largest. I think with Jupiter you can fit 24 earths in it. (or something like that.) It could be that the cores failed to initiate then sustain any manner of prolonged fusion. If they had become suns then it makes me wonder what the solar system would be like then? Would the two have eventually been pulled into one another?

Perhaps because of the gravitational fields, maybe they would've been pulled closer to the sun or even catapulted away from the main sun.

With the sun I read that the sun is a sort of nuclear reactor of sorts. It was long promoted that the sun burned hydrogen as "fuel" but in order for that to happen, there would have to be massive amounts of hydrogen being produced in the universe to satisfy the needs of our sun and others as well.
The sun, as I understand, also produces vast amounts of electricity and magnetic fields. Along with the immense pressure I am assuming that atoms of hydrogen are split and refused.

I admit I am no genius either but you asked some neat questions. Hopefully there will be others to give you better answers than I have. (I am probably WAY wrong on one or more..maybe)

[ShadowSot]

I admit to no great knowledge myself on astronomy, the main reason I'm replying is to make sure my understanding at the moment is correct or in need of improving.

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1. How moon have size exactly to cover sun during solar eclipse?

  Well... it only does if you're at the right place to view it. Otherwise you see a partial eclipse.  
It's at a distance to where it occasionally in it's rotation blocks out the sun for part of the Earth.
  To a similar point, your thumb is the perfect size to block the sun, for you.

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2. I heard that Jupiter is sun that failed. So is it possible that Jupiter once was Sun or that in future becomes one? Whats the reason why didnt become sun?

Some people consider Jupiter to be a failed sun, but it's to small to have started the fusion process we see in the sun and other stars.
  It'd have to be much larger before it could make it to where ti could sustain fusion, it would have tohave about 75 times the mass it does to become a star.

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3. What makes Hydrogen to fuse into Hellium in our sun?

The fusion is drive by the intense gravity of the sun pushing the atoms together.
I'm sure that's a simplified answer, but I only have a hands in pockets approach to physics.

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4. Is just for curiousity. Who was the greater Kepler or Copernicus?

My vote would be on Johannes Kepler, as it was he who discovered the laws of planetary motions.

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5. Is there any study to show effect of cosmic rays on our body, nature or similar?

Unfiltered cosmic rays are dangerous, here on Earth we're shield by our atmosphere. However, in space or on planets like Mars where there's no or minimal protection from the atmosphere it's a signficant consideration in plans for space travel.

Wiki has a article on the health effects.

[MID]

the L, on 26 August 2011 - 08:34 PM, said:

Well, I admit ignorance about Astronomy. I have some basic knowledge from school and few documentraries but I have more questions opened. Where do I start? Hm..

1. How moon have size exactly to cover sun during solar eclipse?

Thanks in advance.

These are great questions L!

As to this one, it's true that the Moon and Sun are the same angular diameter from our vantage point here on the planet earth, despite the fact that the Sun's really immensely larger than the Moon.
The reason we see them the same, and the Moon will cover the Sun exactly, more or less, during a total solar eclipse, is because the Moon's much closer to the Earth than the Sun is.

try a little experiment to illustrate this principal:

Take a golfball in one hand, and a softball in the other.  Hold them both at arm's length and you'll see the difference in size easily, right?
Now, make the golf ball look the same size as the softball.  How.  You know!  By moving it closer to you until it appears the same size.  That's the reason the Moon and Sun are the same apparent size, and the Moon thus covers the Sun so completely in a total eclipse. It's closer!

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2. I heard that Jupiter is sun that failed. So is it possible that Jupiter once was Sun or that in future becomes one? Whats the reason why didnt become sun?

That's a commonly used way of describing Jupiter-- a "Sun that failed".  Mostly because Jupiter is made up of gasses, like a Sun, but it's simply not big enough, not massive enough to have gravitationally collapsed into high enough pressures to ignite the gasses and start nuclear reactions, like those of a star.  Jupiter basically is too puny to be a star.  It's got the ingredients, but not enough muscle!  Ity's kind of like weiging 120 lbs and wanting to play football with the big boys. Not quite enough mass there!

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3. What makes Hydrogen to fuse into Hellium in our sun?

Very simply: extreme pressures and temperatures.

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4. Is just for curiousity. Who was the greater Kepler or Copernicus?

I don't think you can rank these people like that L.
Their contributions to science are both equally important.
Thus, they both have major craters named for them on the Moon (It takes some pretty special stuff to get major craters named after you! )



5

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. Is there any study to show effect of cosmic rays on our body, nature or similar?

Shadow gave you a link to learn more about cosmic rays.  That's a good start.

i have to say, it's pretty refreshing to see questions like yours!
I commend you for your curiosity, and your great questions.
I hope the answers some of us gave you are sufficient.

Please feel free to ask again, should you have any further questions!

[ninjadude]

the L, on 26 August 2011 - 08:34 PM, said:

1. How moon have size exactly to cover sun during solar eclipse?

An easier answer than those given so far. The moon fits exactly because we have incredible dumb luck. In the far distant past, it did not, it in the far distant future. it will not. The moon's distance from the earth is not constant.

The answers to the other stuff is right on.

[MID]

ninjadude, on 27 August 2011 - 01:20 AM, said:

An easier answer than those given so far. The moon fits exactly because we have incredible dumb luck.

You know, that's probably true!  Luck just so happened to result in something that is 2160 miles in diameter and located roughly 240,000 miles away appearing to be the same angular size as an object 400 times larger and located almost 400 times farther away!

Cool stuff when you think about it!

[the L]

Ryu, on 26 August 2011 - 08:57 PM, said:

...The moon is far closer to us than the sun so when it is in proper position, it moves in front of the sun, obscuring it from our point of view. HOWEVER..depending on where you are, some people will see a total eclipse while in other countries they may only have a partial eclipse.
...

I wonder too what would our solar system look like if Jupiter was Sun? Also If sun is nuclear reactor that use hydrogen why shouldnt we head in that direction. Science look for all types of energy sources instead to copy nature?

On the moon thing. I understand how sun eclipse happen just dont understand how is that balanced.

[the L]

ShadowSot, on 26 August 2011 - 09:15 PM, said:

The fusion is drive by the intense gravity of the sun pushing the atoms together.


My vote would be on Johannes Kepler, as it was he who discovered the laws of planetary motions.

Unfiltered cosmic rays are dangerous, here on Earth we're shield by our atmosphere. However, in space or on planets like Mars where there's no or minimal protection from the atmosphere it's a signficant consideration in plans for space travel.

Wiki has a article on the health effects.

Thanks on link ShadowSot. I will read it. I realy wonder how cosmic rays start. What cause them...


cosmic rays can damage DNA...from wiki
I wonder is cosmic rays are responsoble for DNA mutations? Maybe some good mutations happend because of cosmic rays, maybe we evolve because of them...Just guessing.

Edited by the L, 27 August 2011 - 08:32 PM.

[the L]

MID, on 26 August 2011 - 10:25 PM, said:

As to this one, it's true that the Moon and Sun are the same angular diameter from our vantage point here on the planet earth, despite the fact that the Sun's really immensely larger than the Moon.
The reason we see them the same, and the Moon will cover the Sun exactly, more or less, during a total solar eclipse, is because the Moon's much closer to the Earth than the Sun is.

Okay but isnt that BIG coincidence, or should I say miracle? Its wierd that cover Sun exactly.

MID, on 26 August 2011 - 10:25 PM, said:

Very simply: extreme pressures and temperatures.

Isnt temperature result (outcome) of hydrogen fusing into hellium?
Also what happens when star used all hydrogen? Do we have theories for how long sun have hydrogen to fuse into Hellium?

MID, on 26 August 2011 - 10:25 PM, said:

Please feel free to ask again, should you have any further questions!

Thanks for your kind words. And thank you all for answers. I will be free to ask more questions.

[the L]

MID, on 27 August 2011 - 05:10 PM, said:

You know, that's probably true!  Luck just so happened to result in something that is 2160 miles in diameter and located roughly 240,000 miles away appearing to be the same angular size as an object 400 times larger and located almost 400 times farther away!

Cool stuff when you think about it!

That is not luck. Like someone put it on purpose. Wierd.

[the L]

ninjadude, on 27 August 2011 - 01:20 AM, said:

The moon's distance from the earth is not constant.

Okay so In past, during solar eclipse, moon didnt cover the sun? Or it was very close to earth and we didnt see Sun at all.

Also I wonder, in what period Solar and Moon eclipse happens? How many times in a year? In decades?

[the L]

I agree MID. Its just wierd that Sun is 1.392.000 km in diameter and distance from erath 149.600.000 km have same size during Sun eclipse as Moon who has distancee from earth 384.400 km and 3473 km in diameter.

Edited by the L, 27 August 2011 - 08:21 PM.

[the L]

MID, on 26 August 2011 - 10:25 PM, said:

i have to say, it's pretty refreshing to see questions like yours!
I commend you for your curiosity, and your great questions.

Hey its allways better to have right questions then wrong answers.

[MID]

the L, on 27 August 2011 - 08:08 PM, said:

Okay but isnt that BIG coincidence, or should I say miracle? Its wierd that cover Sun exactly.

You can look at it in several different ways, L.
Yes, you could say it's a big cosmic coincidence.  I wouldn't go as far to say it was a miracle....but then again, the cosmic balance we observe, the nature of the heavens, the size of the universe, the wonder of life's evolution on this world...it is rather miraculous!

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Isnt temperature result (outcome) of hydrogen fusing into hellium?

Yes,. and temperature is also the result of pressure.  However, there still has to be extreme pressure (which will produce more temperature)  in order to start the reaction of fusion, which will in-turn produce more energy!  For instance, it is estimated that at the core of Jupiter, the temperatures get to around 35000 degrees C.  That is still not enough for fusion of hydrogen into helium to take place!  Alot more mass is necessary!

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Also what happens when star used all hydrogen? Do we have theories for how long sun have hydrogen to fuse into Hellium?

Several different things can happen, depending upon (again) the mass of the star. In our Sun's case, the star will begin to expand it's outer layers as the hydrogen fuel is used up and the core of the star begins to contract.  The shell of the star will them be shed in a planetary nebula, leaving a white dwarf star which will gradually cool over many billions of years.  It's a pretty complex process, with several variations depending on the mass of the Star.

For our Sun, we're looking at around 4-5 billion years before this process begins.

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Thanks for your kind words. And thank you all for answers. I will be free to ask more questions.

We thank you!

[the L]

Thanks MID.

Can you answer on post 11.