Airbrush

Great stuff Arch. I like those kind of ideas. But I think it is easy to explain, Rare Earth. Conditions for intelligent life to evolve are few and far between. Maybe our solar system is uniquely gifted with favorable conditions protecting it from the deadly energy and conditions that exist throughout space. Maybe asteroid impacts are far more common in the universe than in our little oasis. And cosmic rays may be bad too.

Not spanning galaxies. Even the most massive black hole known, OJ287 at 18 Billion Solar, has an accretion disk only a little larger than our solar system, about 1/5 of a light year (extending out to about the middle of the inner Oort Cloud), and superimposed over our solar system it has an event horizon extending only to within the orbit of Mercury. More correct to say "spanning interstellar space". http://stardate.org/resources/news/blackholes/200801a.html My favorite bit of trivia: If the Earth was crushed down into a black hole the event horizon would form a sphere less than one inch in diameter! It would look like a small flat-black super ball.

Are we in a spiral arm? Where are we located with respect to the nearest spiral arm? How long does it take us to pass thru a spiral arm? Will the distance to the nearest stars increase, and by how much, when we pass out of a spiral arm?

My questions about the WMAP all-sky image is what is the significance of that cold blob area near the center? It resembles the Atlantic Ocean with the Americas on the left and Europe/Africa on the right. I thought the WMAP proved that the CMB was almost the same everywhere indicating that inflation had to happen. Or are the variations in temperature very tiny?

Do you believe in the Big Bang? Correct me if I am wrong but it seems to me at the time of the Big Bang all matter began relative motion apart from a state of very high density. After that everything was coasting with its' original momentum which was enough to overcome the universes combined gravity. At first it may have slowed relative motion, because of gravity, but then dark energy overcame that and then expansion of space increased. In addition to that original inertia of all matter, space also expands adding to the relative motion speed apart. Or how would you describe it?

Thanks for the correct terminology. Everything has Big Bang inertia, so what we see is a combination of the original inertia of everything, which implies motion thru space, plus the expansion of space, or cosmological constant, dark energy. Right?

There is no void, because "nature abhors a vacuum". Lots of evidence for things, but no evidence for nothing. However, just to be difficult, there is no way to detect space expanding, only the markers (e.g. galaxy clusters, CMB) are moving apart.

How can you be so sure it is not expanding into anything, or into new areas, when we know nothing about the region beyond the edge of the visible universe?

Your title says little about your post which is all about "frame shifting". Would you like to explain how we can see to the edge of the universe? How is it so obvious? Do you mean we can detect the CMB (cosmic microwave background) which is NOW at a distance from us of about 45 or 46 Billion LY away? I totally agree with you about "frame shifting". Whenever distances to the edge of the universe are discussed the distances should be qualified by WHEN. The distance now or when the light began its' long journey here?

What the universe is expanding into is unknowable. For all we know it is expanding into a sea of green with yellow submarines.

Any volunteers for a one-way mission to Gliese 581 at only 20.5 ly?

I don't think there is a paradox. The Fermi Paradox is based on too many optimistic assumptions about how many intelligent space-traveling civilizations there are. Perhaps they are so very rare and far apart, that they haven't found us yet. Or they don't explore space as much as we like to think. Maybe long-distance space travel is more difficult than we think. We were brain-washed by scifi to think it is easy. They may have explored out to a few hundred light years, and called it quits.

Interesting post Djrams80. Is that your picture in the top right? What I would like on the Moon is an NEO detection station on the far side of the moon. That would always face away from Earth and sweep space for moving dots. What makes helium-3 a must have? I still would rather spend most of our space exploration money on planetary defence systems. Why not have bases in Antarctica that learn to be self-sufficient? That would prepare them for the Moon. The low Moon gravity will cause serious physical problems over the long term. Unless they figure out how to have artificial gravity on the Moon.

See the story below. I heard on the radio it was moving between 50 to 100 Kilometers per second. They said crashing into gas clouds created a greater explosion than if it hit a solid surface. http://news.cnet.com/8301-19514_3-10291824-239.html

A supermassive white hole? What makes cosmologists so sure the origin of the universe started with a singularity or a tiny point? The big bang could have started expanding from a region of indeterminable size. Think of a gateway thru which the universe passed into this space-time. If you walk thru a doorway, you don't emerge as a tiny atom on the other side.

The big bang erased all trace of whatever existed before it. I doubt there was "nothing" before the big bang, but there is no way to prove it. It is hard to imagine what existed then. Something certainly existed before the big bang, the conditions that caused it.

We probably won't get hit, but it CAN happen any time. Tunguska-sized objects are not all identified and can destroy a city or worse. If they want to play around in space, then do it for something that has real tangible benefits, like survival of our species, rather than bases on the Moon or Mars. There would be more world-wide appreciation for the country(ies) that develop the means to defend ALL people, along with other species. It is the most altruistic of all space missions, better than just frolicking around on the Moon or Mars to answer science questions which robotic probes can do just as well and at far less cost. Such a noble mission of the US and others defending all people and life on earth could cut back on terrorism against the US. So that adds up to political benefits. Then other countries may help out with environmental conservation. Most people in the world don't think so much in probabilities, the way scientists do. If you are a country working on a defense system, you will be admired for that. Even if we do start missions to NEOs it will be a hundred years before viable defense systems are tested and on line, ready for action.

The answer is NEOs! Men have been to the Moon. Send robots there and to Mars. What we really need to do to win the respect of the world is develope a fool-proof defense against bolides. The other projects are very expensive, just for fun. A defense system can save the planet. Yes an extinction level event is very, very unlikely in the near future, but we don't know all the threats. Better to be safe than extinct, or living in the stone age, again.

My bet is that superclusters are gravitationally bound and ALL expansion is BETWEEN superclusters. The reason so many question expansion by saying "Hey look at Andromeda, it is not moving away from us!" is because not enough emphasis is placed on large-scale structure of the universe.

Interesting how often this question is asked. Even in this discussion, after it is explained, the same question is asked again. Here is my question. Do superclusters (which are clusters of clusters) expand at all? Or is all expansion BETWEEN superclusters?

A few years ago the Discovery Channel had a special "If We Had No Moon" or something like that. They speculated that if the massive collision that probably created the Moon had not occurred, the Earth's oceans would be much deeper and there would be little, if any, land above sea level. Had anyone heard that one? Recently I heard on Michio Kaku's radio program "Explorations" that the fact the Moon stabilizes Earth's rotational axis is not as big a factor as previously supposed. If we had no Moon, the Earth's axis would wonder, up to 90 degrees, but major movement would take tens of millions of years and would not be so disasterous to life on Earth.

The Kuiper Belt objects are so far away, they don't concern us as much as NEOs (Near Earth Objects) that cross our path. Yeah, let's get some target practice on some dastardly NEOs!

I don't believe there are any moon-sized asteroids around. So relax, all you need to worry about are Tunguska-sized asteroids and some bigger ones. No big deal.

Yeah, we need to think about "in a pinch". A quick and dirty method may be our only chance with the unannounced objects. Recently a Tunguska-sized object passed us by without us knowing it existed until a couple of days before closest approach. We can get blind-sided any day, with at best only a few days notice, if it comes "out of the Sun", the way fighter planes attack. For short-notice objects we need to take advantage of high closing speed with the object. It will be headed, more or less, directly at us at a very high speed, 10 miles/second or faster. Our only hope will be kinetic impactors or nukes speeding towards it at a comparable speed, so the closing speed will be 20 miles/second or faster. If you can slam enough mass into it, you might divert it just enough. Or nukes timed to explode at the exactly proper moment just a short distance from it so you heat up one side to vaporize and push it just enough. I don't know why we are not already practicing short-notice techniques on nearby asteroids.

Well said. Generally speaking, all the planets in the solar system follow elliptical orbits around the Sun, but NEARLY circular.