Our home planet, Earth | The Society for the Planetary Protection

The only planet known to host life, and its natural features are the subject of several scientific studies. It is the third closest planet to the sun in the solar system, as well as the largest terrestrial planet and the fifth largest altogether. Its two vast polar regions, two somewhat small temperate zones, and a wide equatorial tropical to subtropical region are its most significant climatic features. Precipitation varies greatly depending on location, ranging from several meters to less than a centimeter every year. Salt-water oceans cover 71 percent of the Earth’s surface. The rest is made up of continents and islands, with the Northern Hemisphere having the majority of the populated land.
Earth’s evolution has left traces of the primordial conditions due to geological and biological processes. The exterior surface is separated into multiple tectonic plates that are gradually migrating. With a thick layer of plastic mantle and an iron-filled core that generates a magnetic field, the interior remains active. A solid inner phase and a fluid outer phase make up this iron core. Through dynamo action, convective motion in the core generates electric currents, which in turn form the geomagnetic field.
The introduction of life-forms has dramatically altered air conditions from their initial state, resulting in an ecological balance that stabilizes surface conditions. Despite large regional variations in climate due to latitude and other geographic factors, the long-term average global climate is relatively stable during interglacial periods, and variations of a degree or two in average global temperature have historically had significant effects on the ecological balance and the actual geography of the Earth.

Beyond Earth

Outside the atmospheres of celestial bodies, outer space, commonly known as space, refers to the largely empty regions of the Universe. To distinguish it from airspace, it is referred to as outer space (and terrestrial locations). The atmosphere gradually attenuates with increasing altitude, therefore there is no distinct barrier between Earth’s atmosphere and space. Interplanetary space is the term for the area outside of the Solar System that crosses over into interstellar space near the heliopause.

Several dozen types of organic molecules found to date by microwave spectroscopy, blackbody radiation left over from the Big Bang and the start of the universe, and cosmic rays, which include ionized atomic nuclei and numerous subatomic particles, make up the sparsely populated outer space. Gas, plasma, and dust, as well as tiny meteorites, are also present. There are other evidence of human existence in outer space today, like as debris from prior manned and unmanned launches, which could pose a threat to spacecraft. Periodically, some of this material re-enters the atmosphere.

Despite the fact that Earth is the only planet in the solar system known to support life, evidence suggests that Mars once had liquid water bodies on its surface. Mars may have been capable of generating life for a brief moment in its history. However, the majority of the remaining water on Mars is currently frozen. If there is life on Mars, it is most likely to reside underground, where liquid water is still possible.

Mercury and Venus, the other terrestrial planets, appear to be too hostile to support life as we know it. However, Europa, Jupiter’s fourth-largest moon, is thought to have a subsurface ocean of liquid water that may potentially support life.

Astronomers have begun to find extrasolar Earth analogs, which are planets that are located in the habitable zone of space around a star and might potentially support life as we know it.

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Scientists believe they have discovered the first planet outside the Milky Way

This image marks the potential planet discovered in M51. / Credit: NASA/CXC/SAO/R. DiStefano

NASA claims that a team of scientists has uncovered evidence of a new planet outside the Milky Way. It’s possible that the planet will be the first ever discovered in another galaxy.
According to NASA, the unidentified possible planet, which is around the size of Saturn, was discovered in the spiral galaxy Messier 51, also known as the Whirlpool Galaxy, about 28 million lightyears distant from Earth.

The discovery was made with the Chandra X-ray Observatory, a NASA telescope, and a new approach for searching for planets known as the X-ray transit method. Exoplanets, as defined by NASA, are planets outside of our solar system that are difficult to detect.

Scientists were able to record when an object travels over a star and blocks its X-rays using the new technology. Researchers can learn more about the size and orbit of the putative planet by measuring the duration and strength of the object’s movement.

The researchers’ findings were published in the journal Nature Astronomy on Monday.
“We’re aiming to open up a whole new field for finding other worlds by searching for planet candidates at X-ray wavelengths, an approach that allows us to identify them in other galaxies,” said Rosanne Di Stefano, the study’s lead author and an astrophysicist at the Harvard-Smithsonian Center.

Although the discovery is thrilling, the researchers cautioned that more data is required to prove the planet’s existence, which might take decades. The orbit of the hypothetical planet is so vast that it “would not cross in front of its binary partner again for nearly 70 years,” according to NASA.

“Unfortunately, we’d have to wait decades to witness another transit to establish that we’re seeing a planet,” said Nia Imara, a co-author of the paper and an astrophysicist at the University of California, Santa Cruz. “And we wouldn’t know exactly when to look because of the uncertainties about how long it takes to orbit.”

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