Well, it will be at least a billion years before the sun swells to a red giant and goes nova.
But, in the meantime, we do have a more immediate concern and that is the NEAs or
Near Earth Asteroids.
Any asteroid the crosses the earth's orbit has the potential of hitting the earth. It has happened in the past (the extinction of the dinosaurs) and it will happen again in the future. It's not a question of IF it will happen but a question of WHEN it will happen, and someday it WILL HAPPEN!!! We just don't know when.
Also, any asteroid that passes as close as one million miles from the earth is considered a "near miss" when compared to the scale of the solar system. So far, in recent years, we have had a couple of asteroids pass even closer to us than the moon, less than 230,000 miles away, less than a quarter-million miles.
But now, we know of an asteroid named Apophis that was discovered back in 2004 and it's about 270 meters or more than 800 feet in diameter. That's small as far as asteroids go, and of course, if it were to hit, it won't cause a major extinction event. The asteroid that was responsible for wiping out the dinosaurs and causing most of the life on the planet to become extinct, that one was at least, about 6 miles in diameter. But Apophis is capable of destroying an entire city and wiping our a few million people if it were to hit.
It will pass much closer than any asteroid has in recorded history. It will pass to within a mere 18,000 miles, and that is lower than the orbits our our geo-synchronous satellites! It could very well collide with one of our satellites. That's damn close!
Anyway, here is an article from a web site at:
http://www.kqed.org/quest/blog/2009/03/ ... t-or-miss/
Asteroid Apophisâ??Hit or Miss?
by Ben Burress - March 25th, 2009
Friday the 13th, April, 2029: If you're superstitious, this might not be a good day to schedule a near-Earth asteroid encounter. But, as it happens, that's the day that the Near Earth Asteroid (NEA) Apophis will make a very close flyby of Earth, a once in 800 years event for an asteroid Apophis' size.
Fortunately, scientists have already predicted, 20 years in advance, that this is our lucky day: Apophis won't hit the Earth at that time. Rest assured (pretty much).
Discovered in 2004, Apophis is an asteroid about 270 meters across that orbits the Sun at distances ranging from about one astronomical unit (1 AU; the distance between Earth and the Sun) and about three quarters of an AU. Apophis orbits the Sun once every 323 days.
Apophis is about the same size as the asteroid that
blasted the mile-wide Barringer Crater in Arizona.
Credit: David Roddy, USGS
After its initial discovery, before our knowledge of its orbital trajectory had been refined, astronomers had predicted that there was a small chance it could hit the Earth on April 13, 2029, but as we got a clearer picture of its orbit the probability dwindled to practically nothing. Instead, Apophis will pass by Earth no closer than about 18,000 miles. Whew! Disaster averted, and we didn't even have to send Bruce Willis to deal with it.
But waitâ??that's not all. Though Apophis almost certainly won't hit us in 2029, there's a chance that this close encounter will set the asteroid up for an impact with Earth in 2036â??something like 1 in 45,000.
So, if we know there won't be an impact in 2029, why don't we know whether or not there will be one in 2036? Why all the suspense?
Here's where I pull out my pinball analogy. Think of a pinball machine. The play zone around your flippers represents near-Earth space, the various bumpers up in the field represent all the planets, the Sun, and other large asteroids of the Solar System, and the pinball represents a Near Earth Asteroid, like Apophis.
When the pinball inevitably comes into the play zone, there are two possibilities: either it will hit (or be hit by) one of your flippers and thus be deflected back into the field where it will bounce around some more between bumpers, or it will sail right through that dreaded "window" between the tips of the flippers and fall into the end pocketâ??which represents Terra Firma and a catastrophe if a NEA falls there. As any pinball player knows, it's nearly impossible to predict exactly what path the pinball will follow into the play zone until it gets close.
It's a lot like that with a NEA in the Solar System: as it orbits around the Sun, its course is influenced by the gravitational pull of planets, large asteroids, and potentially smaller asteroids that it might pass close to. A very small deviation in a NEA's direction or speed can, over time, "amplify" into a very large difference in position much farther down the road.
Given the 2029 close encounter with Earth, though we're reasonably confident Apophis won't hit us on that pass, we don't know precisely how that encounter will alter Apophis' orbit. The gravitational interaction between Earth and a NEA passing close by is a complex one, with many variables, not the least of which is Earth's non-uniform gravitational field.
If Apophis passes Earth through precisely the right "window" in 2029â??say, right between the flipper tipsâ??then it could be set up for an impact at its 2036 encounter. That window, called a gravitational keyhole, is only about 600 meters across for the 2029 encounter.
As we gather more data on Apophis, we'll get a better prediction for what may happen in 2036â??but right now the odds are that it will ultimately miss us at that time. That's a good thing, too, because at that time Bruce Willis will be 81 years oldâ?¦ and even John Glenn was only 80 when he returned to spaceâ?¦
Anyway . . . . .
We can be thankful for the Astro-nerds or Astronomy geeks who are patrolling the skies above us for any incoming asteroids, and if we can know well in advance by several years that an asteroid is on a collision course with our planet, then we can do something to deflect it's path by a tiny amount that is enough to cause it to miss the earth entirely, thus saving millions of lives or perhaps even preventing another major extinction event depending on the size of the asteroid so deflected.
So, we have an advantage over the dinosaurs. We can send probes out into space to intercept an asteroid and do something to change it's path, and the sooner it's done the better, because the sooner it's done, the smaller the amount of deflection needs to be to cause it to miss our planet.
But we only have so many astronomers, both professional and amateur sweeping the sky and only so many telescopes. This job can also be done by amateurs as well as professionals. You don't need a really big observatory with a giant telescope. Any amateur astronomer can spot asteroids with a good 8 or 10 inch telescope and the right computer software guiding his telescope. This will free up the most of the professional observatories with their giant telescopes for observing the distant galaxies, because for that, the professional astronomers like to get out their big guns.
Therefore, we need more amateur astronomers patrolling the skies with their telescopes, because some day, some Astronomy geek is going to spot an asteroid, and after carefully tracking it's path and making the necessary calculations, he or she will know that it is on a collision course with our planet, and calculate when it will strike, many years in advance so that we can send out a probe to intercept the asteroid and alter its path so that it will miss us.
Yeah! Some day, some Astronomy geek is going to save our collective ass!
I say that all the sports bores and monkey-boys seriously need to back down and stop bullying the nerds and the geeks in our schools, because the nerd that is being bullied around in high school today, might some day be the one who spots an incoming asteroid, predict it's arrival and collision, and we send out some probes to intercept to prevent a collision from happening.
SO, LISTEN UP MONKEY-BOYS, AND LISTEN TIGHT!!!
YEAH! LISTEN REAL GOOD YOU MACHO PIGS!!!
The Astronomy geek that you're beating up on right now may be the very one who someday saves your bacon! You PIG!!!
So, you monkey-boys need to back off!!!
Back off and let the Astronomy geeks do their job!
I'm fat and sassy! I love to sing & dance & stomp my feet & really rock your world!
