Tag Archives | Atmosphere

Mysterious Electric Blue Clouds Appear Again Over the Poles

Writes Jesus Diaz on Gizmodo:

Every year around this time, mysterious electric blue clouds appear over the North and South pole. They are called noctilucent clouds and they can only be seen in deep twilight, when the Sun is below the horizon. According to NASA, “their origin is still largely a mystery”:

“Various theories associate them with meteoric dust, rocket exhaust, global warming—or some mixture of the three.”

They are the highest clouds, located almost on the edge of space at 54 miles (85 kilometers) from the Earth’s surface, in the mesosphere. They are very difficult to observe, but they appear as white and blue tendrils when they are illuminated by the Sun and the rest of the atmosphere is in our planet’s shadow…

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Outer Space Is Closer Than You Think

1971japanspaceencyclopedia03 Sometimes strange and wondrous things are closer than we realize. For instance, did you know that space is only an hour’s drive away, if you somehow drove your car straight upwards? Perhaps someday you will. Via kottke.org:

Space always seems so far away and much of it actually is. But space is actually quite close to where we are all sitting right now. The Kármán line, the commonly accepted boundary between the Earth’s atmosphere and space, is only 62 miles above sea level.

A distance of 62 miles can covered by a car on the interstate in less than an hour. Stable Earth orbits are achievable at only 100 miles above the Earth, with the ISS and Space Shuttles usually orbiting at a height of ~200 miles.

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