The red planet and the asteroid belt beyond

Through Robert Hazen, Ph.D., George Mason University

We live in an absolute golden age of astronomy, a golden age of planetary exploration. Never before in history has the pace of discovery been so rapid. The red planet, Mars, is by far the most studied of all of our neighbors in the solar system. If a neighboring planet was home to life, Mars is the favorite.

The image shows the landscape of Mars
If there is a chance that a nearby planet is home to life, Mars is the most likely. (Image: Dotted Yeti / Shutterstock)

The characteristics of the red planet

When you think of Mars, think of two words: “water” and “life”.

Mars has an elliptical orbit that is on average one and a half times the Earth-Sun distance. As a result, Mars can be as close to Earth as 60 million kilometers, and it’s not very far by solar system standards. It can also be as far as 400 million kilometers.

A year long of 686 days is equivalent to almost two years, compared to a year on Earth. A day on Mars is coincidentally very close to 24 hours, and that could be of great benefit to future colonists if we ever colonize Mars. Mars is tilted about 20 degrees on its axis. This tilt causes seasons on Mars to be very similar to the seasons on Earth.

Mars has two objects orbiting around it – they are really too small to be called decently sized moons; Phobos and Demos look like captured asteroids. They’re only tens of kilometers in diameter, but they’re moons by definition nonetheless.

Mars has surface markings, and these are easily visible from Earth. Mars has very little atmosphere and we can see these marks prominently with our telescopes; the most obvious are the polar ice caps. These ice caps increase and decrease with the Martian year of 686 days.

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Water on Mars

The planet also shows lighter and darker spots on the surface; reddish areas that appeared to some 19e-th century as linear characteristics.

We got a much better glimpse of Mars with the Mariner space missions in the 1960s, and these returned the first close-up images of the spectacular Martian surface.

We can observe natural valleys carved by water; crater plains; and giant volcanoes. We see vast systems of what appear to be braided streams and water-worn valleys on the surface of Mars, and suggest that Mars once had abundant water and perhaps a much thicker atmosphere than it does today. .

So where has all this water gone? It turns out that at less than half of Earth’s gravity, water molecules can escape into space. It is a very slow and gradual process, but it is an inexorable process. So the water that was once on the surface of Mars probably just escaped, slowly evaporated.

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Mars exploration mission

The Viking Lander missions of the 1970s returned images of a barren, barren and destroyed world, a desert world. The atmospheric pressure of carbon dioxide is only half a percent of the earth’s atmosphere. Even so, there are intense dust storms that detonate the surface with winds of over 100 kilometers per hour; they scour the surface several times.

Image of the red planet, Mars.
The red color of Mars comes from iron oxides. (Image: John BrownX / Shutterstock)

The most spectacular Martian mission to date was the Mars Pathfinder mission, which landed on July 4, 1997. It included both a lander and a 23-pound six-wheel rover named Sojourner. The mission returned spectacular three-dimensional images of the surface. He also had chemical analyzes of rocks, which were found to be very similar to terrestrial rocks.

The red color of Mars, for example, comes from iron oxides, which are very widespread on the surface of the Earth. He also verified that the atmosphere is mostly carbon dioxide, although under much less pressure than at the Earth’s surface.

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Asteroid belt beyond Mars

Beyond Mars we come to the Asteroid Belt, which is a wide swath of rock debris midway to Jupiter, roughly where you might expect to see another Earth planet, by the spacing planets. There are maybe 50,000 objects one kilometer or more in diameter. The asteroid belt is just a bunch of big rocks out there.

Illustration of asteroids in the asteroid belt.
The asteroid belt between Mars and Jupiter is a large swathe of rocky debris. (Image: Jurik Peter / Shutterstock)

According to one theory, Jupiter’s strong gravitational force prevents these objects from clumping together to form a planet. Now every once in a while there will be asteroids passing through the Earth. These are asteroids that are in very elliptical orbits that come in and out of Earth’s orbit.

We are now seeing many prehistoric impact sites on the surface of the Earth, which clearly shows that some of these asteroids hit the Earth from time to time. Indeed, we now have strong evidence that an asteroid with a diameter of about 20 kilometers struck Earth near what is now the Yucatan Peninsula in Mexico. That was about 65 million years ago. This epic explosion led to the extinction of dinosaurs and many other groups of animals and plants.

Some scientists, including American astronomer Carl Sagan, have suggested that these asteroids passing through Earth pose a serious potential threat, perhaps the most serious threat to the survival of the human race, and that they should be mapped in a way. much more detailed. In addition, he recommended that we perhaps develop a space presence, a way to deflect such an asteroid if it ever turns out to be heading towards our planet.

Common questions about the Red Planet and the asteroid belt beyond

Q: How close is Mars to Earth when it is in orbit?

Mars has a elliptical orbit which represents on average one and a half times the Earth-Sun distance. As a result, Mars can be as close to Earth as 60 million kilometers.

Q: What was the Mars Pathfinder mission?

the Mars exploration mission was the most spectacular Martian mission to date. It landed on July 4, 1997. It featured both a lander and a 23-pound six-wheel rover named Sojourner. The mission returned spectacular three-dimensional images of the surface. He also had chemical analyzes of rocks, which were found to be very similar to terrestrial rocks.

Q: What theory tries to explain why the asteroids in the asteroid belt between Mars and Jupiter don’t clump together to form a planet?

According to one theory, the strong gravitational force of Jupiter prevents asteroids in the asteroid belt never to clump together to form a planet.

Keep reading
How did all the liquid water on Mars disappear?
The outer region of the solar system
Ice in the solar system: from lakes to comets


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