WHY IS EARTH KNOWN AS "UNIQUE PLANET" ?EXPLAIN

coz dis is d only planet where the climate supports the life system.

Earth is unique.Earth has many things going for it, that other planets just don’t have. For one, it has large amounts of liquid water. This might not be too special, as Jupiter’s moon Europa also may have liquid water, but it is not certain. Other than maybe Europa, Earth is the only planet that currently has liquid water . Also, Earth has a substantial amount of oxygen that allows it to support life, and it has the perfect amount for fires to burn. If there was too much oxygen, everyone would die of oxygen toxicity, and fires would burn.

Earth has a thick atmosphere, which grants protection to Earth’s residents from harmful UV rays from the sun. It also is the perfect density that it does not crush people, but it isn’t too thin so it allows people to breathe. Also, Earth has a powerful magnetic field that protects it from harmful solar wind and solar flares. The reason Mars is such a barren wasteland with a very thin atmosphere is because it does not have a very strong magnetic field; over time, the Sun blew away its atmosphere. The magnetic field on Earth deflects most solar wind and solar flares, but some wind can get through and interact with the particles in the atmosphere. This is what creates Aurora Borealis, or the Northern lights.

Earth also is a good size to support life. If it was much smaller, it would lose its atmosphere like Mars or Mercury. An interesting aside: Earth is in fact quite small for a planet able to support life; slightly larger planets would actually be more likely to be habitable than ones of Earth’s size. That’s why astronomers often look for exoplanets larger than Earth, because they would more likely be able to support life.

Finally, Earth is the perfect distance from the sun. It is located in an area called the Goldilocks Zone, which is the distance from a star where liquid water is able to be sustained. If Earth were farther away, it would be too cold, and all the water would freeze, like the poles on Mars. If Earth were closer, the water would be boiled off.

In conclusion, Earth is unique because against all odds it manages to be the perfect distance from a star, it is a good size, it has a thick atmosphere, a strong magnetic field, an oxygen rich atmosphere, and it has large amounts of liquid water. All these factors combined allow Earth to be the only planet that is able to support complex life.

First it was formed by a giant collision late in the accretion process, which formed the Earth-Moon system.

As a result of this, Earth has a long-lasting liquid core, plate tectonics which recycle rocks, water and CO2, a magnetic field which protects life from damaging radiation, and a large moon which keeps its axis stable, keeps recycling minerals, and reshaping land masses with tides and provides an intertidal zone where life can transition from sea to land.

Other moons in the Solar-System seem to be mainly smaller captured asteroids or planetoids or formed along with the planet during accretion.

Earth has oceans of open water, and is in the “Goldilocks zone” of the Solar System.

Circumstellar habitable zone - Wikipedia

The Solar System is in the habitable zone of a particularly large galaxy and has a circular orbit which keeps it away from some of the intense radiation in the star forming spiral arms or near the centre. It is also formed from a “metal-rich” accretion disk with plenty of heavy elements. Metallicity - Wikipedia

Does Our Galaxy Have a Habitable Zone? - Universe Today

I’ve got to say, you are one of the luckiest people I’ve ever met.

Not only that, but your lineage happened to be born on a planet, which was in just the right location around just the right kind of star. Not too hot, not too cold, just the right temperature where liquid water, and whatever else was necessary for life to get going. Again, I like your lucky streak.

In fact, you happened to be born into a Universe that has the right physical constants, like the force of gravity or the binding force of atoms, so that stars, planets and even the chemistry of life could happen at all.
But there’s another lottery you won, and you probably didn’t even know about it. You happened to be born on an unassuming, mostly harmless planet orbiting a G-type main sequence star in the habitable zone of the Milky Way.

The Milky Way is a big place, measuring up to 180,000 light years across. It contains 100 to 400 billion stars spread across this enormous volume.

Credit: ESA

We’re located about 27,000 light years away from the center of the Milky Way, and tens of thousands of light-years away from the outer rim.

The Milky Way has some really uninhabitable zones. Down near the center of the galaxy, the density of stars is much greater. And these stars are blasting out a combined radiation that would make it much more unlikely for life to evolve.

Radiation is bad for life. But it gets worse. There’s a huge cloud of comets around the Sun known as the Oort Cloud. Some of the greatest catastrophes in history happened when these comets were kicked into a collision course with the Earth by a passing star. Closer to the galactic core, these disruptions would happen much more often.

There’s another dangerous place you don’t want to be: the galaxy’s spiral arms. These are regions of increased density in the galaxy, where star formation is much more common. And newly forming stars blast out dangerous radiation.

Fortunately, we’re far away from the spiral arms, and we orbit the center of the Milky Way in a nice circular orbit, which means we don’t cross these spiral arms very often.