Welcome to brain stuff from how stuff works, Hey, brain stuff luring vocal bomb here. All things considered, our atmosphere is pretty great. This blanket of nitrogen, oxygen, and other gases keeps the world's temperature nice and habitable while protecting us from harmful UV radiation. To say nothing of this space debris vaporizes for us. Oh yeah, and without all that oxygen in our atmosphere, animal life couldn't survive on
planet Earth. Not a bad resume. But despite its many good qualities, the atmosphere can be a nuisance to astronomy buffs. That's because it distorts light. At night, the atmosphere makes some heavenly bodies appeared to flicker and shimmer. The technical term for this phenomenon is astronomical scintillation. You probably know it by a different name, twinkling like an onion. The atmosphere is made up of layers. At the bottom is the troposphere, which starts right here at ground level on
the planet's surface. Standing about five to nine miles that's eight to four point five kilometers tall, It's where most of Earth's weather events take place. The other layers are in ascending order, The stratosphere mesosphere, thermosphere, and exosphere. There's also a region called the ionosphere, which encompasses parts of both the mesosphere and the thermosphere. These layers have different temperatures. In addition, the air's density varies from level to level.
When starlight enters our atmosphere, it runs into pockets of cool and warm air. The pockets act as big lenses, causing the light to change direction or refract as it passes through them. Yet the lenses are not fixed in place. They move around and change shape as they shift. So does starlight refraction. That's why the stars appear to twinkle. Scintillation affects planets to Mercury, Venus, Mars, and the other planets in our Solar system do twinkle when viewed from
Earth on a clear night. So does our moon. However, the planets twinkled to a barely noticeable degree distance is the main reason stars twinkle more conspicuously than the planets in our Solar system, because the former are so far away, each star looks like a single pinpoint of light, a single pixel. You might say. It's a different story for Earth's moon and our neighboring planets, being a lot closer they're less affected by the atmosphere. Planets and moons appear
as tiny disks up in the sky. The light they emanate comes not from a single point, but from many individual points, all clustered together. These rarely scintillate in unison, which is why planets and moons don't twinkle as dramatically as the stars, So twinkling can only happen when an atmosphere is present. It's for this reason that photos taken by the Hubble telescope looks so clear. There aren't any
atmospheric air pockets to refract the starlight. Earth Bound astronomers use telescopes with adaptive optics systems to compensate for twinkling, making the stars look more stable. Today's episode was written by Mark Mancini and produced by Tyler Clang. Brain Stuff has merch now. You can get phone cases, tote bags, and of course T shirts. Every purchase helps keep the show going and supports us directly. You can find all that stuff at t public dot com slash brain Stuff.
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