Speaker 1: Welcome to Brainstuff, a production of I Heart Radio, Hey
Speaker 1: brain Stuff Lauren Vogelbaum. Here back in movie goers were
Speaker 1: treated to an amazing site Superman reversing the spin of
Speaker 1: the Earth, turning back time in the process and saving
Speaker 1: his beloved Loess preposterous, of course, But what if something
Speaker 1: did change the Earth's rotation? What if the rotation stopped completely?
Speaker 1: Let's get our admittedly far fetched assumptions out on the table. First,
Speaker 1: let's assume that the Earth stopped spinning gradually, as a
Speaker 1: sudden deceleration would mean disaster, and second, will suppose that
Speaker 1: Earth's ecosystems have survived the transition mostly intact. So what
Speaker 1: does this new world look like? For starters? Earth would
Speaker 1: now take a whole year to do what it pulls
Speaker 1: off in a day cycle from night to day and back.
Speaker 1: Cities would spend half the year in darkness and half
Speaker 1: the year in full sunlight, just like the North and
Speaker 1: South Poles do to day. And like the Poles, every
Speaker 1: region would still experience different seasons, but the temperature swings
Speaker 1: from seasoned season would be much greater for areas along
Speaker 1: the equator. An equatorial region would spend infernally hot months
Speaker 1: very close to the Sun, while that area's global counterpart
Speaker 1: would spend dark, frigid months very far away from it.
Speaker 1: That's trouble for the plants and animals that have adapted
Speaker 1: to the climate of a region, and consequently for the
Speaker 1: people living there as well. The polar regions would remain
Speaker 1: relatively stable, except for the part where they would be
Speaker 1: deep under water. In fact, the boundaries between ocean and
Speaker 1: land on a spin free Earth would look nothing like
Speaker 1: they do today. Because the Earth rotates, centrifugal force causes
Speaker 1: the planet to bulge along the equator. No rotation, no bulge.
Speaker 1: Without that bulge, all of the extra water held in
Speaker 1: place along the equator would go rushing back toward the poles.
Speaker 1: Ez We, a company that develops geography focused technology, modeled
Speaker 1: the world's land and oceans after its equatorial bulge subsided
Speaker 1: and found that the Earth would have a band of land,
Speaker 1: one giant supercontinent that circles the equator and separates two
Speaker 1: massive oceans to the north and the south, and Earth's
Speaker 1: magnetic field might go away too. While we're not entirely
Speaker 1: sure how that magnetic field is generated, the leading theory
Speaker 1: states that it's the result of Earth's inter core rotating
Speaker 1: slightly faster than its outer core. Yep, that's two different
Speaker 1: rotations in one planet. Should both of them stop, the
Speaker 1: mechanism behind Earth's magnetic field may as well, leaving us
Speaker 1: exposed to harmful solar winds and other radiation from space.
Speaker 1: So where would that leave us? We humans are an
Speaker 1: adaptable species with powerful technology at our disposal, but survival
Speaker 1: in this new environment would be a challenge. But sure,
Speaker 1: we could try to light our homes in the darkness
Speaker 1: and heat and cool them at great cost during wild
Speaker 1: temperature swings, but not everything would be under our control.
Speaker 1: Would crops survive the extremes of this new world? Could
Speaker 1: any plants? If not, the entire food chain would be
Speaker 1: in danger. Perhaps we could find new crops or modify
Speaker 1: existing ones to tolerate this new environment, or maybe we
Speaker 1: would become dependent on perennials that can survive harsh winters
Speaker 1: and return with warm weather. You have to admit, it
Speaker 1: doesn't feel like you're spinning around the center of the
Speaker 1: Earth at hundreds of miles an hour, So we should
Speaker 1: probably cut our scientific forebears some slack for assuming that
Speaker 1: Earth was stationary and that the Sun rotated around it.
Speaker 1: Thanks to a number of mathematicians and astronomers over the centuries,
Speaker 1: we now know that the Earth spins on its axis
Speaker 1: as it revolves around the Sun. But why does our
Speaker 1: planet spin in the first place. Remember Newton's first law
Speaker 1: of motion. It states that an object remains in whatever
Speaker 1: state of motions in unless another force acts upon it.
Speaker 1: You could say that the Earth is rotating because it's
Speaker 1: been doing that for as long as it's existed. Before
Speaker 1: there were planets in our Solar system, there was a spinning,
Speaker 1: nebulous cloud of dust with our Sun at the center.
Speaker 1: Over time, these dust particles collided into one another and
Speaker 1: began to stick, forming larger and larger rocks and ultimately
Speaker 1: planets through a process known as accretion. But remember the
Speaker 1: cloud of dust or accretion disk, was rotating from the start.
Speaker 1: As the particles that formed the Earth began to stick together,
Speaker 1: that momentum was conserved, causing the growing planet to spin
Speaker 1: faster and faster, much the way that a figure skater
Speaker 1: does when they pull their arms in towards their body.
Speaker 1: By the time the Earth had formed, it had all
Speaker 1: of the angular momentum it would need to keep spinning
Speaker 1: to this very day. And now that we know a
Speaker 1: little bit about how planets and solar systems form, it's
Speaker 1: probably not surprising that not only does our planet spin,
Speaker 1: but all of them do, though not always in the
Speaker 1: same direction. Since stars developed from rotating solar nebula, they
Speaker 1: spin too, But how fast. Measuring the straight line speed of,
Speaker 1: say a car, is a fairly simple and reliable process.
Speaker 1: Measuring the speed of a rotating object like the Earth
Speaker 1: is slightly more complicated. After all, if you stand at
Speaker 1: one of the poles, you'll spin right along with the
Speaker 1: rest of the Earth, but you'll be stationary with respect
Speaker 1: to its center. A stand on the equator, though, and
Speaker 1: you'll have a linear speed of one thousand and thirty
Speaker 1: six miles an hour. That's one thousand, six hundred and
Speaker 1: sixty seven kilometers per hour. That's faster than the speed
Speaker 1: of sound and one of the reasons that we tend
Speaker 1: to launch rockets towards the east. So is there anything
Speaker 1: slowing the Earth's rotation down? Well, sure, but the forces
Speaker 1: changing the speed of the Earth's rotation make an extremely
Speaker 1: small impact. The tides, which are caused by the gravitational
Speaker 1: forces between the Earth, the Sun, and the Moon produce
Speaker 1: tidal friction as they interact with the Earth. That drag
Speaker 1: adds about two point three milliseconds toward day every century.
Speaker 1: Weather systems can change the Earth's rotation too, with winds
Speaker 1: applying a breaking force to the planet's surface. Finally, earthquakes
Speaker 1: can mess with the length of a day by actually
Speaker 1: redistributing the Earth's mass. The two thousand eleven earthquake that
Speaker 1: struck Japan actually accelerated the Earth's spin because it shifted
Speaker 1: the mass towards the equator and shortened the day by
Speaker 1: one point eight microseconds. So the next time you complain
Speaker 1: about the day being too long or too short, don't despair.
Speaker 1: It's changing all the time. Today's episode was written by
Speaker 1: John and Attabury and produced by Tyler clang Or. More
Speaker 1: on this and lots of other topics that you may
Speaker 1: or may not find art stopping visit how stuff works
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