Airbrush

Any planet that was moving at the rate to move it out of the habitable zone would be moving at a rate so great that it would have collided with another planet between Earth and Mars. The early solar system had many smaller planets that crashed and combined until reaching the current equilibrium of all planets in our vicinity are moving in nearly circular orbits. They are not moving outward, or if moving outward at such a low rate that it would not be enough to move out of the habitable zone. So motion outward would have nothing to do with the reason Mars lost its lakes of liquid water. It lost its' liquid water when it lost its magnetic field and its' atmosphere got stripped away by the solar wind.

Mars has not had any liquid water on its' surface for Billions of years. There could be liquid water under the surface of Mars that occasionally breaks thru to the surface. It would freeze almost immediately upon reaching the surface. The best bet for finding evidence for life ever existing on Mars would be by traveling under the surface thru lava tubes. I don't think Curiosity will ever do that.

Nice answer Spyman, thanks for the info!

I also have always had a problem with an original singularity for the entire universe. It just seems too implausible that the entire universe could be contained, even for the tiniest fraction of a second, within an area smaller than a proton. But I am not an expert, and the experts believe this. Interesting idea that each galaxy had its' own little big bang. That resembles a supenova with remnant in the center a neutron star or black hole. The supermassisve black holes at the center of each galaxy could be "mini-big-bang remnants"? I hope an expert tells us how this is not plausible. Maybe the bang would be too great to allow matter to linger near the center to become stars?

Think of the universe as a car, then time for the car is the odometer reading. We don't know what is outside our car, if anything. I doubt that time for our universe is the only time that exists.

I doubt that "most" of what we know will be disproven. Some of it will. When scientists say they "know" something as a fact, that is more than speculation.

Thanks for the correction. I crunch numbers all day as a bookkeeper, and that error is an embarrassment.

See the discussion in http://www.scienceforums.net/topic/69278-chandra-shows-milky-way-is-surrounded-by-halo-of-hot-gas/ But that invisible gas does not add up to 5.25 times as much matter as visible matter.

What you call "absolute nothingness" is a fantasy. There is nothing absolute about nothingness. The universe "puked itself into existence from something that seems very nothing-like, but not absolutely nothing.

Sunspots are just areas that are lower temperature than the surrounding Sun's surface. They are very bright and only appear dark by extreme filtering in telescopes.

I like the questions you raise and good observations, but when you said 6x as much dark matter as light matter, that is a slight exaggeration. According to Wiki there is 5.25 times as much DM as LM. "...its [DM] existence and properties are inferred from its gravitational effects on visible matter, radiation, and the large scale structure of the universe. Dark matter is estimated to constitute 84% of the matter in the universe and 23% of the mass-energy.[2]" http://en.wikipedia.org/wiki/Dark_matter 84/23 = 5.25x Does light matter (everything that is not dark matter) include all the invisible gas, dust, black holes, brown dwarfs, invisible planets and moons, and asteroids in the universe?

I vaguely recall hearing that the amount of gas and dust in our galaxy, and perhaps all galaxies, is about the same mass as the mass of all visible stars in a galaxy. Also dark matter is estimated to be over 5 times as massive as the ordinary matter.

That helps a great deal. Thank you.

I don't understand this process. Could you elaborate in simpler language? Are you saying that the accretion disk that formed around our Sun reached high enough temperatures to melt the space dust without them collecting into large bodies that (thru their gravitational pressure) developed a molten interior?

This above sounds like a very good answer. On Earth with a thick atmosphere, it seems like space dust will get caught in the atmosphere and not slam into the surface. It will gently fall to Earth, without melting. Sand-sized particles and larger, however, will burn up in the atmosphere.

In the early 1970s, when the Apollo missions were all over the news, the Soviet Union, and every other nation on Earth, would have been very eager to prove the US was faking the Moon landings. It would also have been extremely embarassing to NASA, the president, and the entire nation, if any other nation could prove the Moon missions were a hoax. It was nearly impossible to fake the Apollo missions.

Yes, we will see transits in only about 0.5% of stars with planets. Later they will extrapolate that whatever transits they detect, the actual number is about 200 times what they can see. But the recent news I heard is they were seeing more small planets than larger ones. This would lead one to suppose there are very many Earth-sized planets. Yet, I was watching "How the Universe Works" on the Science Channel, and they said the closest thing they can find to Earth-like is the 4th planet out from Gliese, which is twice Earth's size. It's been over 3 years since the mission began. So why don't they see more smaller planets? Maybe the program is based on data only about 2 years old?

I heard that all asteroids are composed of dust as fine as smoke particles that stick together electrostatically. How can that fine dust become solid rock or metal? It must become molten and that requires a great mass, maybe not "giant" but at least "rather big". Also the molten metals will fall to the center of the molten rock of rather big asteroids. So initially asteroids and meteors are very fragile dust piles that will easily fragment when they crash into each other. The solid ones, that we are most familiar with, must be pieces of "rather big" ones that smashed into other rather big ones and fragmented. The molten fragments cool into solid rock and metallic chunks (the metals originating in the very centers of large asteroids). The ones that reach Earth must be rather robust fragments of "rather big" ones, because a fragile dust pile will not go very far before getting blasted back into fine dust by the solid objects around it. That dust will have to start accretion again painfully slowly.

If Earth-like planets were very common, we would have detected a lot of them already from the Kepler Mission. Kepler is watching about 150,000 stars, the vast majority of which are smaller than the Sun. This means the Goldilocks Zone for these smaller stars is closer to the star than in our solar system. This means they should have seen more planets with periods of shorter than one year. They are waiting until they see 3 transits before confirming a planet. There has been plenty of time already to have seen habitable planets around smaller stars, and we haven't seen them. They jump to a wild conclusion that there are 50 Billion planets in our galaxy and if only 1% of these are Earth-like, than there must be half a Billion Earth-like planets in our galaxy. Who is interested in Earth-like planets farther away than about a thousand light years? I am only interested in LOCAL Earth-like planets, that we could possibly travel to in the next few thousand years. Let me know if you feel my exasperation.

That is what I thought before, but think about it. In order to be made of rock or metal it had to be in a molten state, and that only happens inside of giant asteroids that have a molten interior. So when you see meteorite hunters using a metal detector, they are searching for metal pieces that were once in the core of giant asteroids that crashing into other giant asteroids so that Billions of rock and metal fragments went flying off in every direction.

Correct me if I am wrong, but I think these rocky and metallic meteors are the results of collisions between massive asteroids. They are the fragments that explode outward. So these heavy meteors were originally inside giant asteroids that collided and broke up into pieces, and metallic meteors came from the cores of these giant exploded asteroids. Otherwise, small meteors would be puff balls that easily break up into dust. The puff ball first generation meteors accumulate to form giant asteroids. They never are hard like rock or metal until after they are melted inside giant asteroids. This means the asteroid belt is most composed of broken fragments of ancient giant asteroids. Right?

Interesting way to ask a question. Have you ever thought of proof reading your post and inserting spaces between words and sentences? David Levy also has that tendency to omit spaces between words. Are you David? Anyhow, I appreciate your enthusiasm for astronomy. Yes, the heavy elements are created when massive stars supernova, and the Earth formed from the remnants of supernovas. What is your question?

The sun's energy comes from converting hydrogen into helium. It loses mass that way, but it also loses mass blasting away the sun's surface mass which is mostly hydrogen plasma into space. And maybe someone is going to report how much mass the Sun loses through solar wind, flares, and coronal mass ejections. I don't feel like looking it up right now.

Then you haven't seen the new video of activity on our Sun. The prominances, flares, coronal mass ejections, and generally boiling surface are only visible thru extreme filtering, and they are very "fancy".

Yes, we are seeing the light rays on the telescope glass, not actually on the star. The light you see has traveled from the star.