Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hi
Speaker 1: brain Stuff. I'm Lauren vogel Bom and this is another
Speaker 1: classic episode. In this one, we dip into the everyday
Speaker 1: science of why the stars and our skies, most of
Speaker 1: which emit fairly constant light, appear to twinkle. Hey, brain Stuff,
Speaker 1: Lauren Vogel bomb Here. All things considered, our atmosphere is
Speaker 1: pretty great. This blanket of nitrogen, oxygen, and other gases
Speaker 1: keeps the world's temperature nice and habitable while protecting us
Speaker 1: from harmful U V radiation, to say nothing of this
Speaker 1: space debris it vaporizes for us. Oh yeah, and without
Speaker 1: all that oxygen in our atmosphere, animal life couldn't survive
Speaker 1: on planet Earth. Not a bad resume. But despite its
Speaker 1: many good qualities, the atmosphere can be a nuisance to
Speaker 1: astronomy buffs. That's because it distorts light. At night, the
Speaker 1: atmosphere makes some heavenly bodies appear to flicker and shimmer.
Speaker 1: The technical term for this phenomenon is astronomical scintillation. You
Speaker 1: probably know it by a different name, twinkling like an onion.
Speaker 1: The atmosphere is made up of layers. At the bottom
Speaker 1: is the troposphere, which starts right here at ground level
Speaker 1: on the planet's surface, standing about five to nine miles
Speaker 1: that's eight to four point five kilometers tall. It's where
Speaker 1: most of Earth's weather events take place. The other layers
Speaker 1: are in ascending order, the stratosphere, mesosphere, thermosphere, and exosphere.
Speaker 1: There's also a region called the ionosphere, which encompasses parts
Speaker 1: of both the mesosphere and the thermosphere. These layers have
Speaker 1: different temperatures. In addition, the air's density varies from level
Speaker 1: to level. When starlight enters our atmosphere, it runs into
Speaker 1: pockets of cool and warm air. The pockets act as
Speaker 1: big lenses, causing the light to change direction or refract
Speaker 1: as it passes through them. Yet the lenses are not
Speaker 1: fixed in place. They move around in a shape as
Speaker 1: they shift. So does starlight refraction. That's why the stars
Speaker 1: appear to twinkle. Scintillation affects planets to Mercury, Venus, Mars,
Speaker 1: and the other planets in our Solar system do twinkle
Speaker 1: when viewed from Earth on a clear night. So does
Speaker 1: our moon. However, the planets twinkled to a barely noticeable
Speaker 1: degree distance is the main reason stars twinkle. More conspicuously
Speaker 1: than the planets in our Solar system. Because the former
Speaker 1: are so far away, each star looks like a single
Speaker 1: pinpoint of light, a single pixel. You might say. It's
Speaker 1: a different story for Earth's moon and our neighboring planets,
Speaker 1: being a lot closer, they are less affected by the atmosphere.
Speaker 1: Planets and moons appear as tiny disks up in the sky.
Speaker 1: The light they emanate comes not from a single point,
Speaker 1: but from many individual points, all clustered together. These rarely
Speaker 1: scintillate in unison, which is why planets and moons don't
Speaker 1: twinkle as dramatically as the stars. So twinkling can only
Speaker 1: happen an atmosphere is present. It's for this reason that
Speaker 1: photos taken by the Hubble telescope looks so clear. There
Speaker 1: aren't any atmospheric air pockets to refract the starlight. Earthbound
Speaker 1: astronomers use telescopes with adaptive optics systems to compensate for twinkling,
Speaker 1: making the stars look more stable. Today's episode is based
Speaker 1: on the article why do stars Twinkle? On how stuff
Speaker 1: works dot com, written by Mark Mancini. Brain Stuff is
Speaker 1: production of by Heart Radio in partnership with how Stuff Works.
Speaker 1: Dot com and it is produced by Tyler Clang with
Speaker 1: assistance from Ramsey Young. For more podcasts from My Heart Radio,
Speaker 1: visit the air heart Radio app, Apple Podcasts, or wherever
Speaker 1: you listen into your favorite shows.