On Discovery.com, I learned that most meteors burn up in Earth's atmosphere.
AHH the ATMOSPHERE!
AHhhhhh!
ahhhhh.
// But what happens to those that don't?
Hello Meteor.
Trace here for DNews.
Meteors and missiles can hit the ground with massive force.
The 1908 Tunguska Impact in Siberia flattened 2,000 square kilometers of Russian forest
with an explosion 1,000 times greater than the bomb dropped on Hiroshima.
The meteor left a crater, likely created local firestorms raised by superheated air, and
particles from the impact may have cooled Earth's climate,!
Tiny things hit planet Earth all the time, but they're usually not fast enough or large
enough to worry anyone.
Observations from satellites suggest anywhere from 1 to 300 metric tons of dust hit the
Earth, every.
day.
Assuming 100 tons, evenly across the whole surface we'd gain around point zero two nanometers
every year to the radius of our planet.
You can see some of these things as they fly through the atmosphere - anything over 2 millimeters
in size can create a streak of friction-spawned burnup.
We call them shooting stars, but they're just dust and bits of rock.
If a meteoroid is large enough to make it through our atmosphere and dent the solid
surface of our planet -- at least the size of a marble -- then it gets real.
Most of us know what happens to the stuff ON the surface, destruction, dust clouds,
etc; but new research from Duke University simulated high-speed impacts on sand and soil
so now we know what happens UNDER the surface too.
They based it on missiles, but it works for meteors too.
When an object hits the surface at high speed the soil doesn't move out of the way, but
actually solidifies.
Think of it like a crowd of people, or a pack of snow -- the faster you try to move through
the mass -- the more difficult it becomes.
The researchers dropped a metal rod with a rounded end onto a pack of beads designed
to simulate soil.
They varied the strength of the beads to simulate speeds from 67 to 670 miles an hour (6 to
300 m/s) and found as it sped up, more of the beads took the force of the impact, more
quickly, spreading the kinetic energy over a wide area of soil.
As the projectile speed increased, the particles of soil couldn't get out of the way fast enough,
When you think about it, this isn't a staggering discovery, but it's useful for the production
of bunker busting missiles -- it was funded by the Defense Threat Reduction Agency,.
AND it shows why, when a meteor hits the ground, it doesn't just burrow into the planet.
All that kinetic energy dissipates through the soil at such a rapid rate, and creates
a blast crater.
And in case you're wondering if ALL that energy could change the orbit of our planet, Earth
is real big, y'all.
We're orbiting at around 67,000 miles an hour (108k kph) and we're quite massive.
If you were to blow a 100 mile-thick (160km) chunk of North America off the face of the
Earth; we'd only alter the Earth's momentum by about 50 miles an hour (80kph).
Meteoroid strikes like the Tunguska event do happen every 50 to 100 years or so, so
we'll likely see one in our lifetime!
And now you know what's going on both above AND below that crater.
We got some awesome questions last time we asked, so we're asking again, what do you
want to know about science?
What should we talk about in a future DNews?