Airbrush

"A mixture of hydrocarbons, such as the methane/ethane lakes detected on Titan by the Cassini spacecraft, could act as a solvent over a wide range of temperatures but would lack polarity. "Isaac Asimov, the biochemist and science fiction writer, suggested that poly-lipids could form a substitute for proteins in a non-polar solvent such as methane or liquid hydrogen. "A proposal has been made that life on Mars may exist and be using a mixture of water and hydrogen peroxide as its solvent. A 61.2 percent (by weight) mix of water and hydrogen peroxide has a freezing point of -56.5 degrees Celsius, and also tends to super-cool rather than crystallize. It is also hygroscopic, an advantage in a water-scarce environment." http://en.wikipedia.org/wiki/Alternative_biochemistry#Other_solvents I don't understand these fully. Does it imply that a solvent of methane/ethane could be promising as a medium for exotic life?

With inflation there is no telling how fast a universe can expand, perhaps with infinite speed.

No, the subatomic particles are not "flying around in all directions". The electrons were shoved into the neucleus, so there is no distance between nuclei. That is why neutron stars are so dense, and everything is staying put. Not lots of empty space in the heart of a "nuetron" star, hahahahaha. I think there was an episode of The Universe that stated that neutron stars were in a strange liquid state. Can you imagine what a neutron star would look like up close?

Fascinating discussion, thanks for those intriguing contributions. The difference between finite and infinite, is an infinity. Is everyone in agreement that the universe is probably infinite and so time would be also? Or at least it seems that way.

It is silly to assume that our time is an absolute. Our time may have begun with the big bang, but time in general is probably eternal. You think our universe is all there is, or ever was? You think our universe popped out of nothing? Not likely.

Like others stated previously, I believe the two black holes would merge and whatever energetic reaction, the matter-antimatter explosion, would be contained by the new black hole which will then have the mass of both. None of the energy could escape. The question is how can these ever encounter each other? Maybe if there was a galaxy of antimatter that had a black hole thrown out of it so that it traveled intergalactically to encounter a normal matter black hole. That would be a very unlikely event, but theoretically an interesting question.

Interesting question about evidence for stellar black holes. There is enough to convince Stephen Hawking. "In June 1990 Stephen Hawking conceeded a bet (made in 1974) with Kip Thorne. He agreed that the Cygnus X-1 system contained a black hole. For over 200 years since John Michell described "dark stars" (stars massive enough to stop even light escaping from their surfaces), and Einstein's General Theory of Relativity predicted them, black holes had been an astronomical enigma. However, even since Hawking conceeded the bet the inability to directly observe black holes left some astronomers still unconvinced. Slowly the case for the existence of black holes has been built by indirect observational evidence." I thought they had observed binaries with an invisible partner. The only way to explain the visible star's movement is the gravity from a black hole. The motion of stars in the center of our Milky Way around Saggitarius A could only be an object of millions of solar masses to cause the stars to move that fast and in such small orbits. "An enormous X-ray burst in the centre of the galaxy RX J1242-11 has been observed with the Chandra and XMM-Newton X-ray telescopes by an international team of astronomers. This outburst, one of the most extreme ever detected in a galaxy, was most likely caused by gas from a destroyed star that was heated to millions of degrees Celsius before being swallowed by a centrally located supermassive black hole. The energy liberated in the process was equivalent to a supernova explosion. "Now, with all the data in hand, we have the smoking gun proof that this spectacular event has occurred," said coauthor Gunther Hasinger, of Max Planck Institute for Extraterrestrial Physics (MPE). The black hole in the centre of the galaxy RX J1242-11 is estimated to have a mass of about 100 million solar masses. The astronomers believe about one percent of the star's mass was accreted, by the black hole. This small amount is consistent with predictions that the momentum and energy of the accretion process will cause most of the destroyed star's gas to be flung away from the black hole. " http://astronomy.swin.edu.au/sao/astronomynews/astronews2004s1.xml

Interesting idea, but if there is no motion of atoms how can there be heat? So the singularity in a black hole may not have any heat.

Thanks for the size relationships of subatomic particles, Michel. I will try to remember those and consider the incredible scales. A sheet of paper is 1,000,000 atoms thick. And the proton is a tiny speck inside a huge area of empty space. What a brain sizzler!

The most massive stars ever seen would be invisible at the distance of quasars. Quasars are NOT stars of any sort. Only a supermassive black hole can produce that tremendous energy output.

You are confusing dark matter with the galactic central black hole. The rotation of the outer galaxy can only be explained by a lot of invisible dark matter. The visible matter in our Milky Way (stars, gas, and dust) is about one Trillion solar masses, and more than half of that is gas and dust. That is a LOT of gas and dust. And yet all that mass does not explain the outer galactic rotation. The central supermassive black hole is only a few Million solar masses. That is very tiny compared to a visible mass of a Trillion solar masses of ordinary matter, and another several Trillion solar masses of dark matter.

The universe is less than 14 Billion years old. We can see galaxies up to a distance, measured in YEARS, of light we see now that is about 13 Billion YEARS OLD. And that is not 13 Billion light years away. That galaxy was much closer to us when the light left it. We can even calculate how far away from us it was when the light, we see now, left it. That galaxy is about 30 Billion light years away from us NOW. The cosmic background radiation is the most distant thing we can detect, and that is about 45 Billion light years away from us NOW. Review the Ned Wright Calculator under the sticky topic "Cosmo Basics" by Martin. Maybe someone can explain how it works. At one time Martin helped us use the calculator, but I forget how. It is not very friendly to cosmo beginners, such as me. You need to know red-shift values. Someone should create a more user-friendly calculator, using light years instead of gigaparsecs. http://www.astro.ucla.edu/~wright/CosmoCalc.html

By reporting that they have discovered "over 200 interesting candidates", does that mean they have detected over 200 FIRST transits? Then I believe the next year is critical in finding orbital periods for other potential Earths. If most other stars in our galaxy are smaller than our sun, then the habitable zones around such stars is probably a narrower range of distances from the star, and closer to the star, maybe the distance between Venus and Earth? Correct me if I'm wrong, then most, if not all, candidates for Earth-like planets, with liquid water, would show another transit in less than one year. That will be before 5-12-2011. What an exciting realization we will have then! Longer than one-year orbital periods may be possible if the other Earths are much more, or less, massive than Earth, yet habitable? Is that why Kepler is a 3-year plus mission? How long can Kepler continue to operate? After it is done with that region of space it, can it switch to another region and start looking again?

Kepler began operating on 5-12-09. As of the last data download they have 200 interesting planet candidates. "The Science Team continues to analyze data collected by Kepler. Kepler’s list of interesting candidates has grown to well over 200. Meanwhile, the constellation Cygnus has returned to the night sky of the northern hemisphere, so the Science Team is actively involved in ground-based follow-up observations of Kepler’s candidate targets." http://kepler.nasa.gov/news/mmu/index.cfm?FuseAction=ShowNews&NewsID=39 Like the scientist on "The Universe" said, what Kepler is doing is so simple and yet so profound, that "it brings tears to his eyes." Me too.

A quasar is a supermassive black hole SBH in the process of feeding. It is like a giant rotating donut with energy blasting out of its' poles. Is this peculiarly extreme energy generated simply by gas and dust being heated to extreme temperatures, or is matter and antimatter combining? I would like to know. You can see a quasar only if its' pole is pointed in our general direction. If we are looking down the jet, then it's called a blasar. If it is pointed enough away from us, we would not even see it, but perhaps we could detect the radio waves?

When in doubt, wiki it out. http://en.wikipedia.org/wiki/Quasar Then come back and ask some more specific questions.

OK then, not a cone, maybe a curve as you propose. Is a banked race track a curved bank? I think the floor can be perfectly flat from the center out, and obviously a curve along the circle. Anyone else want to vote on whether race tracks are a curved or flat bank?

I appreciate the advice. I wish I had a scanner so I could post a drawing of the Moon Station. Exactly Mr. Skeptic, a very slow merry-go-round. You enter and exit at the center. Crew quarters are around the perimeter, and the floor is banked inward like a race track.

By spin up and spin down do you mean stopping the merri-go-round so people can get on, and then spin up to one G? You already explained it better than I could: IA: "...when you spin eough...the combined force of gravity and centripetal [or centrifugal] acceleration equal 1 g... the floor would appear to those inside to be level but to anyone outside it'll be at an angle." I think the merri-go-round can spin at constant rate. It would be underground. You enter down an elevator (or stairs) to the base of the structure. Then you proceed out to the crew cabin ring on the outer edge. As you proceed outward the g forces increase.

Exactly Mr. Alien. Except the crew quarters need not be limited to a chamber at the end of a boom, but the entire outer ring. Like in the movie 2001 A Space Odyssey, remember how Dave was jogging along the inner side of the ring?

Think of a car going around a race track that is banked inward. The driver will feel one G vertically, plus some G's (or fraction of G) at an angle to vertical. Or think of a merri-go-round at the park. Instead of a flat horizontal floor, the floor of the merri-go-round is banked inward at a slight angle. The idea is to increase the low G forces on the Moon or Mars, in such a way that the people inside it will not notice anything other than Earth-like one G gravity, at an angle from vertical, so that to them gravity seems to be downward only. The floor would only be curved around the perimeter, but a vector from the central axel outward would not be curved, but flat like the banked race track.

I still haven't heard anyone say my centrifuge idea would not work to attain one g gravity on the surface of the Moon or Mars. Underground dwelling on Moon or Mars is the way to go, to shield the people from radiation. They enter down a central tunnel and then turn towards the "Merri-go-round" that brings the low gravity up to one G. Genetically altering humans is way more complicated. Or, if my centrifuge won't work, you can have perfect one G gravity in orbit around the Moon or Mars, or any asteroid, on the inner edge of the giant bicycle wheel. That will allow humans to spend more time in normal Earth-like conditions.

Thanks for the corrections DH. I just heard Mars had 1/9 the mass of Earth and jumped to the wild conclusion that meant Mars gravity was 1/9 of Earth. As for how long a manned mission to Mars would take, you think from launch until returning to Earth would normally take less than one year? If so maybe 1/3 g is not too bad for human physiology, but a long-term base on the Moon might employ artificial gravity merri-go-round crew quarters for 1 g over a period of years. Merged post follows: Consecutive posts merged Yes, but that will stimulate robotics for space missions. Things like Kepler and Mars rovers can learn great stuff for us without the encombrance of humans on board, with the additional problem of returning them safely to Earth.

Thanks for your insights Panglos. I like the race-track analogy. I was thinking like a Merri-go-round with the crew quarters at a tilt towards the center. The crew would not be conscious of the rotation. They would only feel normal, steady, 1 g. Over years in zero gravity will probably, eventually bring bad physical effects. So space travelers, for their health and longevity, should stay in an artificial 1 g gravity on one-way, multi-generational space missions, or even on several-year long missions to Mars, the asteroids, or even Jupiter's moons.

Is it possible to build a shelter for people on Mars that rotates in such a way to create one G gravity on the surface of Mars? I was thinking of the slowly rotating "bicyle-wheel" space station that can create one G gravity anywhere in outer space. If that concept was slightly modified to rotate at an angle, the humans inside the Mars, or Moon, station would experience one G gravity. I was thinking of a cone shaped structure. The crew compartments would be at an angle of about 20 degrees from horizontal. Except for that, I think it would be very bad for people to spend such a long time in one nineth G gravity that exists on Mars. Human missions to Mars would take years for a round trip. Or the crew could spend most of their time in orbit around Mars in artificial gravity, and then only visit the planet for a few days or weeks at a time, before they return to normal one G gravity, to recover, in orbit around Mars.