Universe Today

Humanity may end in many different ways. We might kill ourselves through nuclear war, or die from a global disease epidemic. Like all the species on Earth, we’ll eventually be gone. But life will survive and continue to evolve into new and interesting forms. But even the Earth won’t last forever. Eventually, our planet too will end.

So, how will the Earth end? It all depends on how the Sun ends.

The Sun is a happy main sequence star right now, but as it nears the end of its life in about 7.5 billion years, it will begin to swell up as a red giant star. Its size will get so large that it will encompass the orbits of the inner planets. Mercury and Venus will be consumed within the Sun.

As the Sun grows, it will let off ferocious solar winds that dwarf its current winds. These winds will cause the Sun to lose a tremendous amount of mass, and this mass loss will cause the orbit of the planets to start spiraling outward. Scientists used to think that this spiraling outward might actually save Earth. Instead of being consumed by the Sun, it would keep spiraling, always keeping one step away from the expanding Sun.

The current thinking is that it’s not going to be fast enough. Although Earth’s orbit will be spiraling outward, it won’t be fast enough to keep pace with the expansion of the Sun as it becomes a red giant. At some point, roughly 7.5 billion years from now, Earth will end; it’ll be gobbled up just like Mercury and Venus before it.

By that time, let’s hope that future humans have relocated to the outer Solar System. By that time, the habitability zone around the Sun will have expanded to the point that water can be a liquid around Kuiper belt objects, like the dwarf planet Pluto. Can you imagine sitting on a beach on Pluto?

You can read more about the end of the Earth in this article. And you can read about the end of the entire Universe in this article.

If you’re talking about majestic ice rings, like we see around Saturn, Uranus or Jupiter, then no, Earth doesn’t have rings, and probably never did. If there was any ring of dust orbiting the planet, we’d see it.

It’s possible that there were rings orbiting Earth in the past. Some scientists think that Earth’s gravity could have broken up a comet or asteroid that got too close to the planet, but didn’t actually collide. This is similar to what happened to Comet Shoemaker/Levy 9 that eventually crashed into Jupiter. First the giant planet tore the comet up, and then the pieces crashed into the planet on a later orbit.

In the case of Earth, it might have held onto a few ice particles that would have then orbited the planet, and eventually crashed through our atmosphere and burned up. Even the smallest particles of ice or dust create spectacular meteors in the sky, so there was a ring right now, we’d see these impacts all the time.

Other scientists think that a giant asteroid impact with Earth, such as the one the killed the dinosaurs 65 million years ago, might have kicked up a huge ring of debris around the planet. This ring would cast a shadow down on the surface of the Earth, changing the planet’s climate, and could last for a few million years at most.

Finally, humans have put up an artificial ring in the past. The US Military launched 480 million copper needles into orbit around Earth in a project called Project West Ford. Scientists could bounce radio signals off the needles and communicate between two locations on Earth. This worked for a few months after launch, until the needles were too far dispersed to allow for communication. In theory, if needles were continuously launched, it would be a functioning communications system, but it’s not necessary with modern communications satellites.

So Earth probably did have temporary rings in the past after asteroid impacts or cometary flybys, but Earth doesn’t have rings today.

The Earth has a mass of 5.97×10²⁴ kg.

You can also check out these books about the planet Earth from Amazon.com for more detailed information.

If you could actually break up the planet into its various parts, you’d get 32% iron, 30% oxygen, 15% silicon, 14% magnesium, and then all the other elements, with sulfur, nickel, calcium and aluminum being the most common.

The density of Earth is 5.5 g/cm³. This is actually the densest planet in the Solar System; however, this is partly because of the size of Earth. The next most dense planet is Mercury, and it would actually be more dense than Earth if it wasn’t so small. Earth pulls at itself with so much gravity, that it compacts down tighter than Mercury.

How did scientists find out the mass of Earth? By studying how things fall towards it. Gravity is created from mass. The more mass an object has, the more gravity it will pull with. If you can calculate how an object is being accelerated by the gravity of an object, like Earth, you can determine its mass.

In fact, astronomers didn’t accurately know the mass of Mercury or Venus until they finally put spacecraft into orbit around them. They had rough estimates, but once there were orbiting spacecraft, they could make the final mass calculations. We know the mass of Pluto because we can calculate the orbit of its moon Charon.

Of all the Jovian related questions that we get here at Universe Today, what is Jupiter made of is one of the most common. Jupiter is mainly composed of hydrogen and helium just like a star. Answering that question seems to open a flood of other questions about the gas giant, so here are some facts about Jupiter that should answer quite a few of them.

Jupiter does not have enough mass to ignite fusion and become a star like our Sun. Without that mass, Jupiter is also too cold for fusion. If Jupiter were to become 80 times more massive it would be able to generate enough heat for fusion through gravitational compression. Given that there isn’t that much mass in our Solar System, outside of the Sun, it is impossible for Jupiter to become a star. Can you imagine how scorched and barren all of the planets would be if ours was a binary star system?

Spectral analysis of Jupiter has revealed that in addition to hydrogen and helium, the planet is made of water, methane and ammonia. Those elements are in trace amounts. The core of the planet is thought to contain some rock and metallic hydrogen. Scientists estimate that the core is heated to 36,000 K. The planet is not just a ball of gas that you would be able to drop straight through. In addition to the rocky/molten metallic hydrogen core, there is a layer of liquid hydrogen and helium and areas where the hydrogen is in a supercritical state, meaning that it does not have distinct gas and liquid phases.

Another frequent question about Jupiter is about the ”stripes” that can be seen. Those stripes are actually an effect of the fast rotation of the planet. To be more specific, they are due to the combination of the planet’s rotation and that its gases are more intensely heated at the equator than the poles. This is similar to why the Earth has trade winds near the equator and jet streams near the poles…rising air interacts with the coriolis effect of the rotation and causes sideways deflections. Jupiter rotates much faster and has a thicker atmosphere, so its coriolis effect is much stronger, thus the stripes. Try this link for a more in depth explanation of the striations(stripes).

Just asking what is Jupiter made of only brings up a whole other set of questions. Be sure to keep looking and you will find plenty to stump your friends and teachers with.

We have written many articles about Jupiter for Universe Today. Here’s an article about the color of Jupiter, and here’s an article about the missions to Jupiter.

If you’d like more information on Jupiter, check out Hubblesite’s News Releases about Jupiter, and here’s a link to NASA’s Solar System Exploration Guide to Jupiter.

We’ve also recorded an episode of Astronomy Cast just about Jupiter. Listen here, Episode 56: Jupiter.

Sources:

• NASA: Solar System Exploration – Jupiter
• NASA – What is Jupiter?

Jupiter has been known since very ancient times, so how did Jupiter get its name? While it had many names throughout history, the Roman empire had the greatest influence over a wide portion of modern society, so the names accorded to planets by the Romans still hold sway over astronomy. The Romans named the planet after their king of gods, Jupiter, who was also the god of the sky and of thunder. Why choose to name the planet Jupiter? It was the largest object in the sky; therefore the most powerful; therefore Jupiter.

In the Roman pantheon, Jupiter began as the sky god, concerned mainly with wine festivals and associated with the sacred oak of the Capitol. Eventually, he was attributed the spoils of war and became a god of war. It was believed that he caused the armies to stand strong and be victorious. He was the main witness in all oaths. Jupiter was the central god in the Capitoline Triad along with Juno and Minerva. He remained Rome’s chief official deity throughout the Republican and Imperial eras, until the pagan system was replaced by Christianity. Jupiter granted Rome supremacy because he was ”the fount of the auspices upon which the relationship of the city with the gods rested”. He personified the divine authority of Rome’s highest offices, internal organization, and external relations: his image in the Republican and Imperial Capitol bore regalia associated with Rome’s ancient kings and the highest consular and Imperial honors. Roman consuls swore their oath of office in Jupiter’s name. To thank him for his help, and to secure his continued support, they offered him a white, castrated ox with gilded horns.

It is common practice for a planet, moon, and many other celestial bodies to get their names from Greek or Roman mythology as well as derive their astronomical symbol from that particular personality. Some examples are Neptune the God of the Sea, Mars the God of War, Mercury the Messenger, Saturn the God of Time and father of Jupiter, Uranus the father of Saturn, Venus the Goddess of Love, and Earth, well, Earth is the only planet to buck the Greco-Roman tradition.

The answer to how did Jupiter get its name is very simple. If you delve into the planet much deeper, you will find that the planet itself is a mystery that scientists are still trying to unravel.

We have written many articles about Jupiter for Universe Today. Here’s an article about how long it takes to get to Jupiter, and here’s an article about the temperature of Jupiter.

If you’d like more information on Jupiter, check out Hubblesite’s News Releases about Jupiter, and here’s a link to NASA’s Solar System Exploration Guide to Jupiter.

We’ve also recorded an episode of Astronomy Cast just about Jupiter. Listen here, Episode 56: Jupiter.

Sources:
NASA Solar System Exploration Guide
NASA StarChild