human activity today is comparable to the destructive force of the meteor that hit mexico 65 million years ago, causing the extinction that occured before this one presently.
133217
I think it is nature's way.\nWhen things in nature get too out of balance, at some point it turns around and evens out. I would like to see the earth's envionment restored at any cost. We are not as important as we would like to believe.
451965
It doesn't.  The dinosaurs existed millions of years before mankind. They died off around 65 million years ago.
284865
UPDATED!!!\n\nIt is taken seriously, and is now generally accepted as the primary cause of the dinosaurs' demise.  there may have been additional factors, but a meteorite impact is considered to be the biggest one.\n\nFor a long time, however, it was believed that meteroites only struck the earth in the past, and after that initial bombardment, the danger passed.  And most scientists demanded a "smoking gun."  A crater.  That crater was finally found...under water.  Off of the Yucatan Penninsula.  When the meteorite first made contact with the surface of the earth, the top point of the giant rock was six miles in the sky!!  It left a crater 25 miles deep.  Imagine standing on the eastern edge of the Grand Canyon.  If that was the Yucatan Crater, the other side of it would have engulfed the casinos in Las Vegas, Nevada!\n\nThe confirmation that it was an asteroid (or meteorite) strike that killed the dinosaurs was the detection of an element called iridium, which is common in space, but rare on earth.  Another indicator is the presence of shocked quartz close to the area of impact.  There are no normal geological processes powerful enough to shock quartz, but a meteorite, if it was big enough, could do it.  Then as the meteorite and the rock with which it impacts is vaporized and blown up into the earths atmosphere, the huge cloud of dust spreads out over the world and eventually settles back down\n\nScientists can tell when the impact occured because after a certain level of geological stratus (layers of sediment laid down over time), dinosaurs are no longer found.  At all.  When they analysed the materials in this layer of sedentary rock, they found unusually high levels of iridium.\n\nSuch impacts are not necessarily periodic events.  Such a thing absolutely will happen to the earth again.  Not if.  When.  And nobody knows when it will happen.  Astronomers have identified thousands of Near Earth Objects.  Any one of these could be the next to strike us, or perhaps one that we missed.\n\nBut it WILL happen.\n\n"if the planet would have been in the outer reaches how can it really be so impactful that it jolted numerous rocks towards earth"\n\nBecause that far out in space, very small changes in direction can have major impacts on the objects trajectory after it has traveled millions or billions of miles.  If you aim a rifle at the bullsey of a target that is 100 meters away and move the barrel end of the rifle just one centimeter, the bullet may miss the target completely.  Just that small distance can be a big miss at a long range.  Likewise, if an asteroid is on a trajectory that doesn't put earth in any danger makes only a slight change, possibly no more than the width of a human hair, it may wind up on a path that will cause it to crash into earth, or a different planet.  This change in the asteroid's path may be caused by the gravitational pull of a nearby planet, or by one asteroid gently bumping into another.  And this can happen anywhere.  While the asteroid is in orbit within our solar system, or in what is known as the "Asteroid Belt."\n\n"also if the planet is undiscovered how can they say anything about its involvement with earth being peiodic"\n\nGood question.  For a long time, scientists suspected that there was another planet beyond Pluto.  The reasons for this were that although this other planet could not be seen, its gravitational effects on other objects could be detected.  I don't know what the specifics of this process\nwere, but perhaps they measured a slight "wobble" in the orbit of pluto that had to have been caused by something with enough mass to cause the wobble.  Astronomers referred to this object as Planet X.  This planet has now been discovered and verified.  It was named Xena.\n\nIt should also be noted that the cause of a change in an asteroid's path doesn't have to be cused by a planet that is very far away.  There are
292847
an event that is effecting the atmosphere today was the mass production of cars and industrial sites in the world. this is hurtin the atmoshperic ozone layer.the carbon monozide coming out of these things is whats doing all the damage
281158
earth is a living thing man, it is still not stable, but you have to look at it in time frames... we've only been here for so long.. it was stable for the dinousaurs for a while.. at least before it got hit with a comet, it had to go back and fix itself
241134
Yes, it's going pretty fast! When you think that 150 years ago there were no cars or airplanes. Pretty freaky.\nNothing moved this fast in the past 1,500 years.\nAlso, going off on a tangent a bit... Did you know that 90% of all the extinct creatures that we know about (including all the dinosaurs) have become extinct in the past 150 years!\nMaybe it's all going too fast.
194902
humans just hav only 500 yeras more bcaz the polarcaps r melting and it may caz a global warming and will distroy then whole human life..so human wont b ther 2 look like something after 1000 years...
318270
actually we saw a movie about this in science, we will not be alive because there will be an ice age that happens in cycles. think about it, we will not last because we do bad when it is only 30 degrees f outside. plus, 1 million years is not that long for evolution compared to the eras is the past ex precambrian was 3900 million years long.
580641
there is a chance that there have been two of the same fingerprints to exist on two different persons in the last thousands of years.
675852
a meteor is going to pass very close to the earth on that day...check out\nhttp://english.ohmynews.com/articleview/article_view.asp?at_code=341846
208736
Extinct species, if not extinct by human activity (shooting them, cutting their forests down, etc.), have extinct for a reason - they did not fit well to the enviournment.\nRecreation of such species may destabilize the delicate balance of nature.\nMoreover, any human interferance with nature, whether trying to do good or bad, can only harm it.\n\nThere are two (1.5) reasons. I think you can start with these, and probably the rest will come to mind after writing this. If not, I believe that other people will have further ideas.\n\nGood luck!
108928
They are leftover from our evolutionary past.
174116
yeh, a meteorit and a galaxy are coming to earth. Don't worry, they come only after 2 milion years...;))
78167
The prevailing theory at this time is an asteroid impact that caused a nuclear winter. more than half the life on earth is thought to have become extinct at this time. I believe it was at the beginning of the cenazoic era. as evidence there is a layer of iridium at this geologic layer that covers the entire planet. Otherwise iridium is pretty rare on earth but quite common in asteroids.\n\nWhile this event may have contributed to the onset of an iceage, the energies involved were probably not great enough to give credit for an iceage.
171915
Evolution isn't something that happens instantly, it is a slow process that takes a long time. Humans actually have only been around for a few thousand years and "civilized" humans have only been around for 10,000 years. In fact, hominids (upright walking apes that are all extinct except for humans) have only been around for less than 2 million years. We are evolving slowly but by the time we radically change, we will not notice because the change would have been very very slow.
642920
you found a meteorite.
108256
Actually many mammals were recorded as fleeing to higher ground before the tsunami, even before the water's edge starts receding (best way to tell if a tsunami is coming). The earth vibrates at a constant frequency, which is not noticeable to humans, but still effects us (a result of natural selection). Animals however can sense changes in the frequency, which is directly determined by local shifts such as the weather. That is why animals seem to have a certain prescience concerning the weather.