Texas Master Naturalist Brazos Valley Chapter: Up In The Air.....

It’s a bird, it’s a plane, it’s a…. meteor?!? I like to call meteors “Nature’s fireworks”. With the Fourth of July this weekend, instead of writing about mini-rockets explode in the sky, I’d thought I’d write about…. well, rocks exploding in the sky!

There are a lot of phenomena that can be considered Nature’s fireworks… lightning, the aurora, volcanic eruptions… but none can really compare to a meteor shower.

Four-hour time lapse image of the Leonid meteor shower in 1998. Image credit: Juraj Tóth [CC BY-SA 3.0]

Meteor Showers

A meteor shower occurs when cosmic debris enters Earth’s atmosphere and burns up. Most of the time the pieces are small, about the size of a sand grain, so they will completely burn up and never reach the Earth’s surface.

Astronaut Ron Garan, Expedition 28 flight engineer, tweeted this image from the International Space Station in August, 2011 with the following caption: “What a `Shooting Star’ looks like from space, taken yesterday during Perseid Meteor Shower.” Image credit NASA

Meteor showers have a periodicity and are predictable at certain times of the year. These events are related to comets passing close to the Earth and shedding debris. Think about Halley’s Comet coming around every 75 years. It was last here in 1986 and will return again in 2061. The comet has passed by Earth many times and left debris along some of its previous paths. There are two meteor showers associated with the debris trails: the Eta Aquariids occurring in April and May, originating near the constellation Aquarius, and the Orionids, originating from the constellation Orion in October. You can check out StarDate.Org for the 2015 schedule of meteor showers. The next one is coming up in August!

Halley’s Comet March 8, 1986. Image credit: NASA

Meteorites

Sometimes, cosmic debris is big enough to not burn up upon atmospheric entry and will hit the Earth’s surface. Now we call them meteorites.

Meteorites are pretty cool because they can tell you a lot about the origin of the larger extraterrestrial body they came from. For example, a stony meteorite comes from the rocky crust of a small planet (planetoid) while an iron meteorite comes from the core of a planetoid.

Now, Texas is a great place to see meteorites and their craters. Most notable, is the Odessa Crater. Odessa is interesting because it is young enough for the crater to still be seen (only 25,000 years old!) and has plenty of iron meteorite fragments. It is also has a nice little museum/gift shop and is free and open to the public. If you are ever out in west Texas along Highway 20, stop in and check it out!

Odessa meteorite fragments. Left: A big one at 70 pounds from the museum gift shop at the crater. Image credit: Kelly Teague [CC BY-SA 2.0] Right: A much smaller fragment (quarter for scale) and recent gift from TMN... Thanks! :)

Fireballs

Finally, cosmic debris can sometime enter Earth’s atmosphere but just skims the surface and returns to space. These events are called fireballs. As recently as last year, a large fireball was seen in central Texas.

Fireball streaking across the sky similar to one seen in Texas. Image credit: Wikipedia, Public Domain

Since we probably don’t want to wait until August for a meteor shower or the random fireball that streaks across the sky to satisfy our love of nature’s fireworks, it’s probably easier to go out to the local firework display and enjoy the show!