How big would our sun be

[eMTee]

How big would our sun have been 4 billion years ago, and how would it have affected the Earth? and seeing the size of it now...compared to others of the same size, and smaller. How long do you think it will last, before it becomes a black hole?

[UncleAl]

Google

"Hertzsprung-Russell diagram" "stellar evolution" 8460 hits

[eMTee]

How old is our sun? I read that it is 4.5 billion years old. Is this true? because that would make it as old as the Earth, or as old as they found it out to be...and being as it at least had all the eliments in the air to be able to suport life, I am kind of confused about this...because how can the Earth be so complex to have an atmosphere around it and possible life on it at the same time when the sun evolves into the sun? now how old is our moon?..is it younger? if it is, then how would no moon effect the Earth's rotation? and what would happen to the atmosphere if the rotation of the Earth was faster or slower than it is now?

[Buffy]

The conventional wisdom on how solar systems form is that you have a mass of gas and dust that slowly, through the mutual attraction of the mass of that gas and dust starts collapsing, and as it collapses, starts spinning, this spin ultimately forms a disk and at the center where most of the gas and dust is attracted, there is enough matter to form a star, which ignites by virtue of the fact that most of the gas is hydrogen (the most abundant substance in the universe after stupidity according to Harlan Ellison) and in large enough quantities has enough gravitational pressure to do so. The planets form out of the same material that has enough rotational inertia to keep it from falling into the sun, but it clumps and the larger clumps sweep up the smaller clumps like gravitationally driven vacuum cleaners until theres nothing left between the planets.

 

So with that preamble, to answer your question, the Sun is made out of the same batch of gas and dust, so it all ends up having the same "age". We use radioactive carbon dating to determine the age of the earth, and we've got rocks from the Moon and Mars (meteorites from Antartica! No kiddin! knocked off of Mars!) that match the same dates. So yes, the Moon is the same age.

 

The only reason life formed here now, is because the Earth is in an especially auspicious location that is amenable to what we call life. Its easy to conceive of life having evolved on both Mars and Venus, and some have arguments that you could make life on the outer planets too, although it would not look anything like us. Life on the Sun is kind of hard to imagine, since its so hot that the onlything that happens there is that hydrogen, helium and other basic elements fuse and become elements higher on the periodic table of elements, but its pretty much impossible for even molecules to form in such a hostile environment.

 

There are good arguments that if we had no moon and therefore no tides and gravitational pull that may have had an impact on the formation and rotation of the Earth's core, that no life would have evolved on the Earth. Its hard to say. A side note: the conventional theory of the Moon is that a gigantic asteroid--not a pebble like killed the dinosaurs, but an almost-Moon-sized monster--collided with the Earth and the Moon is partly Earth and partly asteroid. Scary!

 

Cheers,

Buffy

[Tormod]

The Earth and the sun was born out of the same planetary nebula. Earth's atmosphere did not happen instantly - first the planet had to cool down, then the atmosphere would start building up. The atmosphere as we see it today is very different that it was a billion years after the planet was born.

 

All the planets in the solar system are of the same age, as are the asteroids and comets.

 

The Moon is likely to be the remnant of a huge impact between the early Earth and a planet-size object. A lot of mass was thrown into space and coagulated around the earth first as a ring, then as a planetesimal which became our moon. So the Moon is also as old as the rest of the system.

 

The sun did not "evolve" into the Sun, it is simply what happens at the centre of planetary nebulae wheb there is enough gravity and hydrogen to start the fusion process. We observe this in other planetary nebulae as well, so there is a lot of observational evidence for this.

 

The Moon does affect the Earth's rotation. As Buffy stated elsewhere, the Earth is slowed about 1.5 milliseconds per century, so you're not likely to experience any huge changes soon. ;)

 

The atmosphere of the Earth does not really depend on the rotational speed unless it was extremely different than what it is now. There is no friction in space so it has nothing to "rub" against except cosmic radiation, the pull from the Moon and Sun, and the outbursts of plasma from the Sun.

 

The current rotation does not affect gravity since the mass of the planet stays the same. However, there is a slingshot effect (which is why we launch most rocket payloads near or as near as possible to the equator - Europe's space port is in French Guyana in the northern South America.). If the Earth were to rotate, say 806 times per day you would fly off into space.

[Tormod]

Buffy, can you stop beating me to the postline? ;)

[Buffy]

Sorry Tormod! You guys said you missed me! Be careful what you wish for! I'm actually holding back on some threads if you can believe it....

 

Cheers!

Buffy

[eMTee]

So the Earth, the Moon and the Sun are all around 4.5 billion years old. in recient studies, they found that the Earth had an atmosphere around it,at least 4.4 billion years ago, complex enough to suport life, and may even have, even at that time. If a meteor the size of the moon, collided into Earth, would the Earth be able to withstand it, and keep intact the atmosphere? seeing that the Moon is already moon size, and that it is made up of both Earth and metoer. Then could the moon have hit the Earth at one time?..and when would it have the time to not disturb the Earth's rotation and gravitational pull?

 

Sorry for all the questions.

[Tormod]

I would be interested in seeing which sources you are using, eMTee.

[eMTee]

Reading about each one seperately (Earth,Moon and Sun), and how they evolved and

formed over time, and considering it possible, is diffrent than putting them togeather and still have the same ideas for each ones evolution, and to have it all fit togeather..and not get in each others. So in order to make the evolution possible, it has to be changed, but then that is another story.

 

What do you mean where do I get my information, I get it from from evolution recourses. but the questions are my questions about it.

[maddog]

How big would our sun have been 4 billion years ago, and how would it have affected the Earth? and seeing the size of it now...compared to others of the same size, and smaller. How long do you think it will last, before it becomes a black hole?

When I was in college the figure I heard from the age of the sun was 6.5 billion. I

guess the evidence from looking at nearby stellar births that it is now thought a star

ignites about the time planets being formed. Since with the birth of a star no evidence

is left lying around, it is still an estimate. As mentioned earlier, the HR diagram has

stellar evolution start as a main sequence from collapse of the cloud. While this star

is burning hydrogen, it stays on the main sequence. Depending on the mass of the

star and class (basically color), will determine how long. Once this fuel is exhausted,

such a star starts collapse again untill Helium burning kicks in. This then has the star

expand out to a giant (or supergiant). For our sun, this would be in about 5 billion

more years. It would then expand its surface out to about the orbit of Mars, thereby

burning up the earth. Our sun will neither ever become a Black Hole nor a Neutron

Star as it doesn't have enough mass. A mass of 3.1 or more to become a Black Hole

and 1.6 or more to become a Neutron star.

 

Hope this is what you were asking. ;)

 

maddog

[Tormod]

What do you mean where do I get my information, I get it from from evolution recourses. but the questions are my questions about it.

 

Okay. Where did this information come from:

 

in recient studies, they found that the Earth had an atmosphere around it,at least 4.4 billion years ago, complex enough to suport life, and may even have, even at that time.

 

Which studies?

 

Here is some basic information about the early atmosphere:

http://www.globalchange.umich.edu/globalchange1/current/lectures/first_billion_years/first_billion_years.html

[eMTee]

ok...I have a question....can oxygen, carbon dioxide...and other life suporting elenents...?...ok, can there be air around the earth without an atmosphere..and could it be able to suport life in the air without an atmosphere? the oldest earth they found dated 4.4 billion years...and they say had the air to suport, and possibly had life. 0.6 billion years younger then some people date the sun as.

[eMTee]

The news about the oldest piece of Earth was from a news article I read not too long ago...they where having a big exhibit to show it off, and to talk about it...and the age of the sun was from a science website...the age of the moon was from a responce on this thread, along with the moon being made up of Earth and meteor, thus I got the impression that it might have been the meteor that hit earth..seeing what was also said in responce to my question.