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Hello Space Fans and welcome to another edition of Space Fan News.
So, this happened today.
Most of you I'm sure have heard of this by now, but early this Morning, 9:20 local time
in the skies over the Ural Mountain city of Chelyabinsk Russia, a meteor broke up. It
was so big and passed by so fast, that the shock wave that was created as it exploded
shattered windows all over the city and caused about 1,200 injuries.
As I make this video, the fate of the meteor is still being investigated, but NASA is reporting
that it broke up in the atmosphere.
The Russian Academy of Sciences says the meteor was 15 meters across and weighed 10 tons and
entered the earth’s atmosphere at a speed of at least 33,000mph (54,000kph) and shattered
between 18 and 32 miles above ground (30 to 50km) and the resulting airburst had the equivalent
yield of a 500 kiloton explosion.
The best account of the events as they unfolded was at the Guardian's website, so go check
it out, I have the link in the description box.
It isn't totally clear whether the meteor was completely destroyed or whether parts
of it landed in a nearby lake, but those details are being investigated.
What is clear is that Russians are really, really good at looking up.
I mean, this event was captured by what seemed to me to be an unusual number of dashboard
mounted webcams. At first, I was really puzzled by this, but I learned while watching the
weekly space hangout from CosmoQuest and Ian O'Neill, editor of Discovery News Space Website,
said that apparently driving in Russia is a very perilous activity and the law enforcement
there is (how can I put this delicately), not very helpful.
Driving in Russia is such a problem, that drivers mount cameras on their dashboards
and record every trip they take so they can have documentation to back up their case should
they need it.
So that's why this bolide was so well video-ed. I think I'm going to get one of those dash
cams for when I'm driving around Baltimore. Driving around here seems a lot like Russia.
Now coincidentally, today was the day everyone was preparing to watch the flyby of an asteroid
known as 2012 DA14. An asteroid coming from a completely different direction and having
nothing whatsoever to do with the Russian Meteor. This asteroid was going to fly 17,200
miles above our heads, that's so close that it was going to pass inside the orbit of our
geosynchronous satellites.
We've known for a long time that it was never going to hit us - and most likely miss the
satellites as well - but this coincidence was more than a little freaky.
2012 DA14 is much bigger than the Russian bolide (bolide is another word for fireball
in the sky). It is 45 meters across and if that one hit us, the resulting explosion would
contain two and a half megatons of energy.
2012 DA14 came at us from the south and travelled North. By Comparison, the Russian meteor came
from a completely different area of the sky, which is why astronomers concluded that these
events are unrelated.
When it passed by, you needed binoculars to see it (and you had to be where the sky was
dark: Austrailia, Eastern Europe and Asia.
Today was a real wakeup call for humanity and highlighted the need for something I've
been advocating for a long time now: the need to find and track as many asteroids in our
Solar System as we can.
People are constantly making up their own disasters: Nibiru, Mayan Calendar Doomsday
Prophecies, all kinds of stuff that isn't real. Well, folks, there's no need for that
nonsense, this is a very real danger facing our civilization.
Unlike Donald Rumsfeld: We know what we don't know. Every telescope ever made over all of
recorded time has found only about 10-20 percent of the total asteroids we know are out there
and we've only found about 4,700 potentially hazardous ones (AKA PHA's) - asteroids that
can hit us.
That's only about half of the PHA's that are in the solar system.
So there's a lot of work to do and we need to get on it. Duck and cover is not an option.
If you're interested in learning more, I would encourage you to look into the b612 foundation,
they are planning to launch a space telescope known as Sentinel in 2018 whose sole purpose
is to look for potentially hazardous asteroids. I'll give you more information on that as
things unfold, but this is a private enterprise, one that definitely needs our support.
I can't think of a more important problem in astronomy that needs solving, and we totally
have the ability to prevent this. If we get struck by an asteroid, we have only ourselves
to blame.
Next, conveniently (and in the "not a minute too soon" category), the day before all this
asteroid/meteor hubbub, scientists from University of California at Santa Barbara have proposed
a system to vaporize asteroids that threaten the Earth.
The system is called DE-STAR, or Directed Energy Solar Targeting of Asteroids and exploRation
- a very awkwardly acronym-ed satellite which they claim is a realistic means of mitigating
potential threats posed to the Earth by asteroids and comets.
DE-STAR is designed to harness the power of the sun and convert it into a massive array
of laser beams that can destroy, or evaporate, asteroids posing a potential threat to Earth.
Another handy feature is that it is equally capable of changing an asteroid's orbit –– deflecting
it away from Earth, or into the Sun –– and may also prove to be a valuable tool for assessing
an asteroid's composition, enabling lucrative, rare-element mining. And it's entirely based
on current technology.
Now, to me that last part is more realistic. If we can detect a PHA early enough to give
us, say a year's notice, then we don't have to deflect it all that much to get it to miss
us, which means we don't have to expend as much energy. A tiny deflection early on becomes
a larger one over time.
If we wait too long, then the required changes to the orbit are much larger and will require
a lot more energy.
In developing the proposal, they calculated the requirements and possibilities for DE-STAR
systems of several sizes, ranging from a desktop device to one measuring 10 kilometers, or
six miles, in diameter. The larger the system, the more it can do.
For example, DE-STAR 2 –– at 100 meters in diameter, about the size of the International
Space Station –– could "start nudging comets or asteroids out of their orbits".
But DE-STAR 4 –– at 10 kilometers in diameter, about 100 times the size of the ISS –– could
deliver 1.4 megatons of energy per day to its target, enough to obliterate an asteroid
500 meters across in one year.
A system that size would be able to move an asteroid the size of 2012 DA14 in about an
hour.
So how practical is this?
They claim this is not some far out idea. They say, "Our proposal assumes a combination
of baseline technology –– where we are today –– and where we almost certainly
will be in the future, without asking for any miracles,".
Well that's always a good thing.
They say that recent and rapid developments in highly efficient conversion of electrical
power to light allow such a solution now, when just 20 years ago it would not have been
realistic.
And that, is Just like downtown.
Well, that's it for this week Space Fans, thank you for watching, and as always, Keep
Looking Up!
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慧星撞地球(俄羅斯)大解密 - Meteor Over Russia; 2012 DA14 Flies By; New System to Vaporize Asteroids

15644 分類 收藏
VoiceTube 發佈於 2013 年 2 月 17 日
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