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11

If the sun was principally composed of Iron, then this would be apparent in the spectrum of light from the sun (which is how we know what stars are made of) (but see comment by @Keith Thompson below, the spectra only tells you about the surface, rather than the core). The fact that all solar physicists bar one seem to think it is made up of hydrogen and ...


8

According to the Case Western Reserve University webpage The Edge of the Solar System (2006) an important consideration is that The whole concept of an "edge" is somewhat inaccurate as far as the solar system is concerned, for there is no physical boundary to it - there is no wall past which there's a sign that says, "Solar System Ends Here." There are, ...


6

Over the year, the sun follows a path known as an annalemma. This is a figure eight shape and is caused by the combination of the Earth's rotation around the Sun and its tilt relative to the plane of the equator. The analemma can be observed by pointing a camera at the sun, and at the same time each month, take a picture and over lay the images: Taking a ...


5

Here's my answer. I'll try to make it as comprehensive as possible. It's pretty hard to define the edge of the solar system. Most people would probably define it as where objects are no longer gravitationally bound to the Sun. That just shifts the question a little, though: Where is that dividing line? To try to answer this, I'll go over the regions of the ...


3

The classification of stars using spectral class is a very useful classification when considering the properties of (the atmosphere of) a star at that moment. If you consider the different stages in human development (embryo, fetus, infant, toddler, etc...), for instance, here one person also continuously changes its class. So it is not ...


3

This has been the subject of many documentaries, many of which are based on scientific observations and associated assumptions of the past in the rocks and out in space. Some are outright bizarre imaginings of people. The Discover Magazine article about this topic lists several possibilities, including the following examples that scientists have evidence of ...


2

Read "Death From the Skies!" by Phil Plait. His list is quite comprehensive, going into what can kill humanity, what could destroy all life on Earth, and what could destroy the Earth itself. I don't have my copy on me at the moment, but IIRC he goes into what damage a meteor of various sizes will do. To avoid further confusion, here is a link to the book ...


2

The end of the Earth and the end of a habitat that can support life are 2 different things. The Earth will not be able to support life as we know it for 4 billion more years. The sun is slowly heating up, and estimates are that in 500 million years, the Earth will be too hot to support life. That being said, life is resilient, and who knows what ...


2

Even if the answer has already been accepted, more evidences can contribute to this thought-provoking topic. I think, as it has been mentioned, eliosismology is a good way to map the interior of the star, but I am not able to argue about it. Another disproof, comes from neutrinos. Interior of Sun can be investigated by neutrinos detection, which do not ...


1

I think Mr. Marsupial's answer should get a star, but to put some of this in layman's terms, here's my answer. The process of fusing iron into other elements, whether within a star or within a laboratory pulls more energy from the reaction than it creates. It is the first element in star evolution that does this, and is therefore associated closely with ...


1

We wouldn't feel the ejection of another planet off the solar system, since the attractive force of distant planets to Earth is very low. Only close encounters of Earth with other planets would cause noticeable up to severe changes on Earth. This would be caused mainly by tidal forces due to different acceleration for different parts of Earth, or by ...


1

The further north you go, the time between sunset and darkness becomes longer, no matter the season. The reason is due to the velocity at that latitude. If there is 10 min of twilight on the equator, then there is $10\sqrt{2}$ min at 45° latitude, 20 min at 60° latitude, ... Added: I used the website that @barrycarter listed above and discovered that there ...



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