Why is iron the end all for stars?

reply to post by Pressurecoocker


Our sun will not fuse new elements. The sun will fuze the heaviest elements in it's body into the heavier elements found through out the universe. Earth Will be completely destroyed by the sun long before it ever get's to a stage where it could super nova. When our sun reaches the Red Giant phase it will consume Earth, as well as mars.

When the Sun does supernova it will merely produce those heavier elements from the lighter elements existing with in it's core.

Originally posted by Hijinx
When the Sun does supernova it will merely produce those heavier elements from the lighter elements existing with in it's core.

That's not going to happen. But you were right about the red giant.

www.nasa.gov...

Will our Sun turn into a supernova? Will it become a black hole? No, our Sun is too small.

I think a star has to be about 8 times as massive as our sun to go supernova.

reply to post by Arbitrageur


It will still undergo a final level of fusion before collapsing into a white dwarf.

So I guess no, not a supernova but it will still "shed" before becoming a white dwarf.

I bumped into this thread earlier. So I shall present the alternate theory briefly.

The heavier elements were present in the Universe right from the start (right from big bang).

The accretion of heavenly bodies always starts with heavy elements which form the core.

The lighter elements which are present in clouds spread out in the galaxy are attracted by the core travelling through the cloud. If the core is massive, the accretion is also relatively large which after a time gives rise to a star.

The 'ignition' of a star happens automatically as temperature at the core keeps on rising as mass accrues, and ultimately reaches the limit that results in ignition.

The core of a star has "both" fusion and fission going on. It is not just "fusion".

The light of the sun contains evidence of all elements found on the earth, not just hydrogen and helium.

It is just that sun has a larger percentage of hydrogen and helium than Earth. That's all. It is logical as massive cores accrue very large amount of gases.

When Earth formed, it did not have features like high elevations and deep depressions as its has today.

It was much flatter and covered by a shallow sea.

Earth's surface has changed much due to accretion of matter from space, which has brought most of the water, carbon, and minerals now found on Earth.

The materials we mine today - from iron to uranium has been mostly brought to earth by asteroids.

Earth sees periods of high asteroid activity, as solar system itself circles around the galaxy center, and sometimes passes through clouds of matter.

Originally posted by GargIndia
I bumped into this thread earlier. So I shall present the alternate theory briefly.

The heavier elements were present in the Universe right from the start (right from big bang).

How can this be an alternate theory when it directly contradicts observation?

Astronomers find pristine gas from the big bang

Two clumps of gas that formed in the opening moments of the Universe's existence have been found by astronomers using telescopes at the W. M. Keck Observatory, the first time that gases never involved in star formation have been detected.

Only the very lightest elements such as hydrogen and helium were formed in the big bang; heavier elements were synthesized a few hundred million years later in the hot furnaces of the first stars and subsequent stellar generations. Although the newly discovered gas clouds were found two billion years after the big bang, they represent the simplest material that existed just seconds after the Universe was born.

“It’s quite exciting, because it’s the first evidence that fully matches the composition of the primordial gas predicted by the big bang theory,” says Michele Fumagalli of the University of California, Santa Cruz, lead author of a paper on the findings published online in Science today.

reply to post by Arbitrageur


You call this "direct" observation. How?

reply to post by Arbitrageur


How do they know this "gas cloud" was formed by "big bang"?

Originally posted by GargIndia
reply to post by Arbitrageur

 

You call this "direct" observation. How?

I said "it directly contradicts observation".

You said that "The heavier elements were present in the Universe right from the start (right from big bang)"
They have found a region without heavier elements, proving your assertion false, unless you can explain how the heavier elements were removed from that region of space.

How do they know this "gas cloud" was formed by "big bang"?

I don't think they are 100% certain of that, but given the big bang theory makes very specific predictions about what would be observed, and the fact that they found this and it happens to match the predictions made by their theory, they feel it's likely to be from the big bang since its composition is so consistent with big bang theory.

If someone had a better explanation for the observation they would probably be interested to hear it.

Originally posted by Pilgrum
reply to post by rickymouse

 

We evolved to use iron atoms in our bodies simply as a vehicle to transport oxygen around in our bloodstreams. A nice example of making good use of what's readily available in an efficient manner. Calcium is a building block for our structural framework of bones and teeth etc.

edit on 9/8/2013 by Pilgrum because: (no reason given)

It is basically called evolution. We use what is commonly available in our environment after billions of years of evolving life . People just do not see the point that our DNA and chemical makeup is truly of earth and no where else hehe.

Originally posted by GargIndia
reply to post by Arbitrageur

 

You call this "direct" observation. How?

As you look out into space, you are looking back into the past. The further away an object is, the "older" it is.

When we look at Alpha Centauri, which is 4.3 light years away, we are seeing how it looked 4.3 years ago. When we look at Rigel in the constellation Orion, we are seeing how it looked 1,500 years ago because it's 1,500 light years away.

When we look at the Andromeda galaxy, we are seeing how it looked 2.5 million years ago because it is that far away in light years.

As we look further away, the stars located in galaxies that are billions of light years away, the spectral analysis of the light shows overall that they are "metal poor", or population II stars.

Younger stars that are closer to us, spectral analysis of their light shows that they are "metal rich" or Population I stars.

Stars located at the hub of our galaxy are much older than our sun and each one shows through spectral analysis of their light that they are "metal poor".

So the trend shows: the older the light from stars going back further and further in time shows us stars that contain very little heavier elements, and much younger, more recently formed stars contain much more heavier elements.

Population III stars are theorized to be much more poor in metals, as they were the very first stars formed in the universe. They are the only stars to not be directly observed at this time, but the trend of those stars that are directly observed and who's light can be analyzed through a spectrum supports this theory.

So Population III stars are theory, but the direct observation of Population I and II stars and the spectral analysis of their light, added to how nuclear fusion works, helps support the theory that the first stars (Population III) were extremely metal poor and helped forge the first heavy elements.

During or possibly immediately after the Big Bang, I read there was only energy and that the energy cooled to form the lightest elements such as Hydrogen. E=mc squared was the equation that covers it. I believe space time warped into loops so that the energy rotates in such a tight spin, it acts like matter. Matter and energy are just different forms of the same basic stuff of the universe. Space itself is still expanding. I've wondered what happens to a light wave when it gets stretched flat due to the expansion of space. Does the light simply dissapear or does it change? Would a photon act like a particle if it's energy got stretched flat over time due to the expansion of space? Some of what I'm talking about happened before there were any stars.

When I speak about light waves getting stretched due to space expanding, this is known as Doppler shift I believe. Light has waves like a sine wave. I'm just explaining what I was talking about a little for those who didn't study Astronomy and probably have no clue what I'm talking about. As an example, I remember an Astronomy question that asked, "How fast are you traveling if a red light appears green?". My funny answer is too fast for the cops to pull you over. In the case of traveling a certain percentage of the speed of light, the Doppler shift compresses the light waves and light will undergo the Doppler shift with more compressed waves. Thus red light with a flatter wave becomes shifted from your point of view and you could see green light. If space expands and it is, then a green star might appear red as the light gets stretched out before it reaches us if it has traveled far enough.

A simpler way to explain it would be to imagine a super long flag with waves in it. Miles long, many thousands or millions or billions or trillions of miles long. The waves represent the frequency of a certain color of light. Each color has a different wave height and depth. Stretch out the flag and green light will shift frequency and appear a different color. I was just wondering what happens if the flag or light frequency got stretched flat. Hopefully this is not off topic since it is related to energy and light.

Originally posted by orionthehunter
When I speak about light waves getting stretched due to space expanding, this is known as Doppler shift I believe.

That is not the modern view, though many years ago it was thought of that way. Now we call it
Cosmological Redshift:

At the time of discovery and development of Hubble's law it was acceptable to explain redshift phenomenon as a Doppler shift in the context of special relativity, and use the Doppler formula to associate redshift z with velocity. Today the velocity-distance relationship of Hubble's law is viewed as a theoretical result with velocity to be connected with observed redshift not by the Doppler effect, but by a cosmological model relating recessional velocity to the expansion of the universe. Even for small z the velocity entering the Hubble law is no longer interpreted as a Doppler effect, although at small z the velocity-redshift relation for both interpretations is the same.

One significant reason for distinction is that the recessional velocity of a Doppler shift can't exceed the speed of light, which is an upper speed limit for velocity.

A cosmological redshift, however can be observed from objects which appear to be receding from Earth faster than the speed of light. Because the objects are not traveling though space faster than the speed of light, the speed limit of c isn't broken.

Here is an interesting paper that tries to clear up some common mis-perceptions:

Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the universe

We show that we can observe galaxies that have, and always have had, recession velocities greater than the speed of light. We explain why this does not violate special relativity and we link these concepts to observational tests. Attempts to restrict recession velocities to less than the speed of light require a special relativistic interpretation of cosmological redshifts. We analyze apparent magnitudes of supernovae and observationally rule out the special relativistic Doppler interpretation of cosmological redshifts at a confidence level of 23 sigma

So they have a confidence level of 23 sigma that it's not Doppler shift...5 sigma or more normally constitutes scientific "proof".

reply to post by Arbitrageur


Thanks for the link and information. I have some reading to do.
I thought there was something odd about the original theory and I see others thought the same.

Originally posted by Arbitrageur

Originally posted by GargIndia
reply to post by Arbitrageur

 

You call this "direct" observation. How?

I said "it directly contradicts observation".

You said that "The heavier elements were present in the Universe right from the start (right from big bang)"
They have found a region without heavier elements, proving your assertion false, unless you can explain how the heavier elements were removed from that region of space.

How do they know this "gas cloud" was formed by "big bang"?

I don't think they are 100% certain of that, but given the big bang theory makes very specific predictions about what would be observed, and the fact that they found this and it happens to match the predictions made by their theory, they feel it's likely to be from the big bang since its composition is so consistent with big bang theory.

If someone had a better explanation for the observation they would probably be interested to hear it.

Can you link to the article of paper about what you say?

Do you have access to a Physics lab? If so, I shall ask to to create an experiment, which will help you to understand what I said.

The red shift (observation that universe is expanding) can happen due to many reasons.

The space around us is NOT empty, as we tend to believe.

There is diffuse gas in the space that we think is empty.

The red/orange color is seen more clearly through a fog as light of this wavelength is absorbed less by gases.

The problem with big bang theory, expanding universe theory etc. are that these are based on certain assumptions.

The "observation" is indirect, and is made to fit into a theory.

reply to post by GargIndia


The cosmic redshift cannot be due to the scattering of light like it happens in the atmosphere. If it were, the images of distant galaxies would be blurred.

reply to post by wildespace


Blurring is a different issue.

The behavior of diffuse gas and dense atmosphere are two different things.

The question to ask is how would a body form from pure hydrogen and helium?

The gases do not clump together. Clumping is necessary to form a body.

What we have are clouds of gas and dust that have directional velocity as well as rotational velocity. These clouds give rise to stars.

The lighter molecules stay to the outside, but heavier molecules migrate to the center of rotation and start to clump together. This is how a star starts forming.

Originally posted by orionthehunter
Thanks for the link and information. I have some reading to do.
I thought there was something odd about the original theory and I see others thought the same.

You're welcome. That paper is actually one of the more readable papers on the topic. I had some misunderstandings myself before reading it, which is not surprising since I got them from physics textbooks, which the authors pointed out had errors or misleading statements.

Originally posted by GargIndia
Can you link to the article of paper about what you say?

I did link to the article.

Do you have access to a Physics lab? If so, I shall ask to to create an experiment, which will help you to understand what I said.

I might be able to get access to the local university lab, but then again maybe not. I'd need to have a good reason to ask.

Originally posted by GargIndia
The question to ask is how would a body form from pure hydrogen and helium?

The gases do not clump together.

Where is your evidence for this claim?

Anything with mass has gravitational attraction, including gases like hydrogen and helium.