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Science (non-SETI) :
Did we already colonized the Milky Way ?
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musicplayer Send message Joined: 17 May 10 Posts: 2442 Credit: 926,046 RAC: 0 |
This reminds me of the movie "Deep Impact". Although maybe another story, we are not supposed to see the material (made of dust) which exists between stars and possibly not only between stars but also between galaxies and maybe even clusters of galaxies. When the meteor depicted in "Deep Impact" hit the Earth, it hit the ocean, but at a shallow angle, like someone standing on a cliff in front of some water and throwing a stone straight forward in a horizontal direction. After a few moments the motion of this stone will be affected by several factors. First air resistance, next gravity from Earth. But gravity is readily thought of as supposedly speeding up the motion of falling objects. The speed of the falling stone in relationship with the ground will increase, not only because of the speed of the object itself, but because of the pull of gravity. When it comes to big meteorites and asteroids, these time frames are so short that the influence of gravity from Earth is possibly insignificant. Still the angle of direction is an important factor. If an asteroid hits open water from straight above in relationship with its impact point, it will create waves in all directions. A similar hit from a meteor as depicted in "Deep Impact" will push up water in the same direction as the one which the meteor was having when entering Earth's atmosphere. The asteroid which made the dinosaurs extinct is thought to have occurred in shallow waters, at an angle, near Yucatan, Mexico, in the same way as depicted in "Deep Impact". The resulting wave from this impact pushed inland and probably destroyed all life in continental U.S.A or maybe even North America as a whole. The shockwave and following cloud of ash from the impact went around the Earth several or many times, air was sucked up into the atmosphere with the result of killing off all high level organism on land as a result. Most of the life in the oceans also vanished as a result of this event. As a result of this impact, life had to start up again from scratch both in water as well as on dry land. |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
To summarize. We do know where the asteroid hit and we can judge it's TNT equivalent. Also, not all life was wiped out. A small mammal survived; perhaps it was underground and it eventually evolved over 250,000,000 years to us homo sapiens. Lots of saps and a few homos apparently. |
john3760 Send message Joined: 9 Feb 11 Posts: 334 Credit: 3,400,979 RAC: 0 |
double post? edited by me john3760 |
john3760 Send message Joined: 9 Feb 11 Posts: 334 Credit: 3,400,979 RAC: 0 |
65,000,000 years ago ? We now know that dinosaurs weren't wiped out during this mass extinction event. All life over a certain size was wiped out,( apart from a few species such as crocodilians which can survive without food for extended periods ,or on rotten carcasses ). It was also a mass extinction event for plant species as well. The animal species which survived the impact,and ensuing years of hardship,were all small and probably could burrow or hide underground when the firestorm engulfed the earth(mammals / reptiles/ insects etc), or live in water ( fish/ reptiles /amphibians etc). Some species may have survived purely because their eggs were buried,and hatched out into a post apocalyptic world. Small dinosaurs survived as well ,we know their descendants today as birds. john3760 p.s @ Michael . The Yukatan crater has been dated to 65,000,000 years ago. In addition to that, there is a worldwide layer of deposited ejecta called the KT boundary layer.This also dates to the same time, plus the deposit is thicker,the closer you get to the crater.This is good way of tying these two things together. You can calculate the mass of ejected material, by measuring the thickness of this layer around the planet,then the force that would be needed to eject this amount of material. You can then calculate the size of the object which must have hit the earth to produce this force. |
musicplayer Send message Joined: 17 May 10 Posts: 2442 Credit: 926,046 RAC: 0 |
The special element which is abundant in meteorites and asteroides is Nickel (or Nikkel in my own language). Atomic number is 28. Checking out with http://en.wikipedia.org/wiki/Nickel gives me this correct syntax for this element. It is now late night here and I am relaxing right now after a somewhat bad day. So, therefore, I also could have said "probably" rather than "possibly" in my previous posting. Anyway, when digging (or making excavations) into the soil, this element is being found as making up a white line of some thickness (a couple of centimeters/decimeters). This tells us how much of this periodic element which was deposited across the Earth as a result of this impact (and other impacts in the past). Similarly, another periodic element which is NOT found in meteorites or asteroides is Cadmium, Atomic number 48. Check out http://en.wikipedia.org/wiki/Cadmium for this periodic element. My best guess is that this element is poisonous to humans. But to be honest, why not stick to the question of the original poster (OP)? Organic molecules, if possibly brought through space by means of "meandering" metorites are indeed acid molecules. Why is it not so when it comes to bases as well or instead of acids? Does there exist a similar base alternative for DNA which is itself an acid and the basis for both life and possibly intelligent life (by means of the ability of thinking as well as dreaming)? Also trees are having a very complex organic molecule (even bigger than DNA) in its organic structure. Plants are green in color because of Magnesium rather than Iron in its molecule core. Sugar is an acid. What about the salt which you may put on your breakfast egg? Salt is NaCl (Natrium/Chloride)or KCl (Kalium/Chloride). Calcium (or Ca) you get inside your body when you drink a glass of milk in the morning. |
skildude Send message Joined: 4 Oct 00 Posts: 9541 Credit: 50,759,529 RAC: 60 |
guess again. the element is iridium. http://en.wikipedia.org/wiki/Iridium K–T boundary presence Iridium is incredibly rare on earth and its origins appear to be almost 100% from asteroids and meteors. In a rich man's house there is no place to spit but his face. Diogenes Of Sinope |
Michael Watson Send message Joined: 7 Feb 08 Posts: 1387 Credit: 2,098,506 RAC: 5 |
The implications of this finding seem remarkable. Assume that very basic forms of life can survive for long periods in space. It is an idea that has been discussed before and found at least plausible. If it is so, it appears that large tracts of interstellar space have been seeded with life, not only from Earth, but from extrasolar planets that have experienced impacts similar to the one at out K-T boundary. There has been the tendency to think of Earth, or at least our solar system, as biologically isolated from the rest of the universe. It begins to appear that a good deal of back and forth mixing; seeding, reseeding and transplanting of life might occur between many different stellar systems. |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 31002 Credit: 53,134,872 RAC: 32 |
Unfortunately the rocket failed or we might have some real idea behind panspermia. http://www.planetary.org/programs/projects/life/ Hopefully there will be another launch opportunity for this important research. |
musicplayer Send message Joined: 17 May 10 Posts: 2442 Credit: 926,046 RAC: 0 |
Yes, skildude. Apparently you corrected my mistake here. I don't think it happens too often, though. As long as we are able to both think as well as dream and also learn something, we trust our brain cells for this capability. Then it is time to consult the doctor or at least a medical book which may be dealing with the relevant subject. The neurological functions of a human brain, which except for the possible ear disturbances you may be having from time to time due to possible illness is created by means of electricity. Also these functions may be creating waves on their own. Do we ever think of electricity as consisting of waves? If someone had the capability of traveling between the stars, one way of surviving such a long journey (except for the constant ageing which may still be occurring) is living in hibernation. Which really is a little more than just a deep sleep. I guess you will not be able to dream very much in such a state. Remember that you still may be traveling at nearly the speed of light. You are not supposed to become very much older during such a long journey. In order to get back up again when you finally arrive at your final destination, you may need to get some kind of a wake-up call. Also you will have to go the same way back again, when you are returning home. |
JLConawayII Send message Joined: 2 Apr 02 Posts: 188 Credit: 2,840,460 RAC: 0 |
2 things bug me: Yes, a good deal of material from such an impact could enter space provided it didn't vaporize in the atmosphere first. We've used a nuclear detonation to launch an object at several times escape velocity, and the K-T impact event was far more powerful than any manmade device. I think the more important question is, would any life actually survive within these chunks of superheated and molten rock? and 2nd : i know it s pretty accepted the theory about a big asteroid hit the earth and made disappeared life and dinosaurs.... but how they can be so sure about its diameters and its mass ? and where it did hit the earth ? they have proof about where it did it ? The impact crater from the event has been identified with a fair degree of confidence as the Chicxulub Impact Crater off the Yucatan Peninsula in Mexico. The age of the crater fits the timeframe for the event, and its size coupled with the resulting worldwide layer of iridium fallout give a good estimate as to the asteroid's size and mass. |
Convergence Send message Joined: 23 Jun 08 Posts: 117 Credit: 2,928,788 RAC: 0 |
While an impact of that magnitude will certainly cause debris to be ejected out into space, space is so vast that the odds of one of these ejected rocks getting to another star system and impacting on an earth-like planet there is quite astronomical. That's if the debris even escapes the Sun's grasp, which it probably won't. |
Allie in Vancouver Send message Joined: 16 Mar 07 Posts: 3949 Credit: 1,604,668 RAC: 0 |
The escape velocity from the Earth's surface is around 11 km/s, and the solar escape velocity (at the distance of the earth from the sun) is about 42 km/s. Meanwile, asteroids and comets can zip along at 50 or more km/s. If it hits at 50 km/s, then it is not so hard to imagine it could kick bits of rock out at 42 km/s. Pure mathematics is, in its way, the poetry of logical ideas. Albert Einstein |
Nick Send message Joined: 11 Oct 11 Posts: 4344 Credit: 3,313,107 RAC: 0 |
then it is not so hard to imagine it could kick bits of rock out at 42 km/s. At this speed then how much of this ejected material would burn up as it passes back up and out through our atmosphere. The Kite Fliers -------------------- Kite fliers: An imaginary club of solo members, those who don't yet belong to a formal team so "fly their own kites" - as the saying goes. |
Allie in Vancouver Send message Joined: 16 Mar 07 Posts: 3949 Credit: 1,604,668 RAC: 0 |
then it is not so hard to imagine it could kick bits of rock out at 42 km/s. Rocks come into the atmosphere everyday and get a little singed but make it to the surface, going the other way wouldn't be much different. As for life surviving the trip: there are bacteria that thrive in deep-sea vents, in volcanoes, and other places that are fairly extreme. Life tends to be pretty darn tough. Pure mathematics is, in its way, the poetry of logical ideas. Albert Einstein |
Nick Send message Joined: 11 Oct 11 Posts: 4344 Credit: 3,313,107 RAC: 0 |
As for life surviving the trip: there are bacteria that thrive in deep-sea vents, in volcanoes, and other places that are fairly extreme. Life tends to be pretty darn tough. Surface bacteria would most probably get annihilated by the radiation out in space. Inner rock bacteria could most probably survive this but still how long can they live, time wise, protected inside a rock. The Kite Fliers -------------------- Kite fliers: An imaginary club of solo members, those who don't yet belong to a formal team so "fly their own kites" - as the saying goes. |
skildude Send message Joined: 4 Oct 00 Posts: 9541 Credit: 50,759,529 RAC: 60 |
As for life surviving the trip: there are bacteria that thrive in deep-sea vents, in volcanoes, and other places that are fairly extreme. Life tends to be pretty darn tough. lets not forget that there is a bacteria that can grow and prefers to grow in the water of Nuclear reactors. So radiation may not be a limitation In a rich man's house there is no place to spit but his face. Diogenes Of Sinope |
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