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?