Posted in Science & Nature

Shooting Star

When an object from outer space enters the Earth’s atmosphere, it starts to burn up and creates a brilliant streak in the sky, which we call a meteor or shooting star. Contrary to popular belief, this is not due to friction with the air in the atmosphere.

An object entering the atmosphere is typically travelling at extraordinary speeds. Most meteors are travelling around 20km/s (or 72000km/h) when they hit the atmosphere. At these speeds, air molecules do not have a chance to move out of the way. The meteor will instead collide into the air molecules, pushing them closer and closer to each other, compressing the air in front of it.

As we know from physics class, compression increases temperature in gases as per the ideal gas law (PV=nRT). The impressive entry speed of these meteors result in so much air compression that their surface can heat up to 1650 degrees Celsius.

The heat boils and breaks apart the contents of the meteor, turning it into superheated plasma that gives off a glow. This is the streak of light that we see in the night sky when we wish upon a shooting star.

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Posted in Science & Nature

Verneshot

If there is one thing we learn about dinosaurs, it is that they were wiped off the face of the Earth by an asteroid impact. Another feasible theory is that a supervolcano eruption completely destroyed the ecosystem, wiping out all life on Earth by either directly destroying them via a massive shockwave (if they were within range), or by slowly starving them as the resultant plumes of smoke would have blotted out the sun for years. But interestingly, scientists looking back over some extinction-level events of the past, discovered signs of both an asteroid strike and a volcanic eruption. This sounds to be extremely implausible, as the odds of both happening in the same era are near impossible (unless there is some extremely vengeful deity that hated the dinosaurs).

One theory that tries to explain all of this is the verneshot theory. To better understand the concept of a verneshot, imagine a cartoon character such as Yosemite Sam (the beloved red-bearded, gunslinging cowboy character on Looney Toons) shooting his gun wildly into the sky. Cartoon logic dictates that his bullets will eventually fall back on some unwary bystander. Now imagine if the Earth did the same thing, but instead of a bullet it shoots a giant piece of rock capable of causing mass extinction into the sky.

A verneshot occurs in a similar way a supervolcano erupts, where there is an incredible build-up of super hot molten rock. A supervolcano would be when this molten rock erupts as lava. In the case of a verneshot, massive amounts of carbon dioxide build up instead, leading to a pressure build-up under the crust. When the pressure becomes too much, the crust explodes, with the piece (of indeterminate size) being rocketed into space. However, the giant rock does not end up in space. Instead, it is only launched to a sub-orbital altitude, meaning it will come crashing back down to Earth due to gravity. Thus, a verneshot is when a volcanic eruption acts as a giant cannon to launch a piece of the Earth into the sky, which falls back to Earth as an asteroid-like object.

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