Name: 為什麼地球沒有環？ (Why Doesn’t Earth Have Rings?)
Uploaded: 2021-01-14T05:24:12.000Z
Duration: 2 min 50 s
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The recent reigning Queen of everything, once said “If you like it, then you shoulda put

基礎被動語態

a ring on it”, well I like the Earth, why wasn’t a ring put on it?

A researcher from the University of Rochester, Eric Mamajek, recently took another look at

some odd readings from a star 420 million light years from Earth. The starlight emanating

from the faraway solar system seemed to dim frequently indicating a planet passing in

front of it. In most cases like this, the dimming lasts a few hours, however this star’s

His interpretation? A scaled up version of Saturn. A big planet with HUGE RINGS. This

planet would be about 10-40 times the size of Jupiter. Its rings? EVEN BIGGER. If they

exist, they would span the width of here to the sun. That’s 93 million miles. It’s

so big, it leaves many scientists skeptical.

So while they still puzzle over that mystery, let’s take a look at why planetary rings

Four of the planets in our solar system have rings, the gas giants, Jupiter and Saturn,

and the ice giants Uranus and Neptune. Their rings aren’t a giant solid disk, they’re

a bunch of smaller rings made up of smaller particles, like bits of rock and dust and

Saturn’s big ring is made up of thousands of smaller wide rings of ice that reflect

a lot of sunlight, so they’re super visible to us on Earth, I mean with a telescope of

course. Galileo first discovered Saturn’s rings in 1610. Jupiter, Uranus, and Neptune’s

rings are thin and dusty, so they’re not as visible to us and took a little longer

to find. Jupiter’s rings weren’t discovered until 1979 by the Voyager 1 space probe and

Neptune’s weren’t found until a decade later, by the Voyager 2 space probe.

Planetary rings form in a few ways: Possibly in the early days when the planets were forming

from a mass of space dust, this debris never made it into the final planet, so it just

kind of hangs out in orbit. Or the rings might form when planetary satellites, like a moon,

get too close and get pulled apart by the planet’s gravity. These two theories could

explain Saturn’s rings. Most of the other planet’s dusty, thin rings formed when their

moons were hit by something and that impact kicked up dust and particles.

The earth had a ring too once. It just coalesced into the moon. So why don’t Saturn’s rings

turn into a moon? The rings are simply too close to the planet. They are within what

is called The Roche Limit named after a French astronomer, Edouard Roche, who calculated

this theoretical limit in 1848. Inside the limit, the debris remains as rings. Outside

of the limit, debris coalesces into larger bodies, like a moon. When a satellite, like

a moon, gets too close to the planet and it can’t withstand the tidal forces caused

by the planet’s gravity, it disintegrates. Our moon is out side of the Earth’s Roche

limit, so it remains spherical. But what if it fell into the Roche Limit? What if the

Earth had rings like Saturn? It would look pretty awesome, something like this.

What do you think? how cool would it be if earth had rings? let us know in the comments