Earth and Venus are nearly the same size.
extraterrestrial...? wait, sorry, it's 'inferior planets'.
I think you mean extrasolar planets. Technically, all planets except Earth are "extraterrestrial." At last report there were almost 900 of them, with more to follow. They aren't a "group" in the usual sense, just a category.
We believe in the existence of extraterrestrial life because of the vastness of the universe, the discovery of planets in habitable zones, and the possibility of similar conditions to Earth on other planets.
Extraterrestrial are unknown humans. They are humans, but different kinds from different planets. Like aliens and UFOs. The scientific community think this is true. They think they come from planets beyond Earth...
They search for extraterrestrial life on other planets.
Venus and Mars are often called Earth's twins because they are rocky planets like Earth, but they have different environments. Venus has a thick toxic atmosphere, while Mars has a thin atmosphere with extreme temperatures.
The remains of extraterrestrial particles found on Earth and its surface are called "cosmic dust" or "extraterrestrial dust." These particles can originate from comets, asteroids, and interstellar space, and they often provide valuable insights into the composition of the solar system and beyond. When collected and analyzed, they help scientists understand processes like the formation of planets and the origins of life.
At this time we have no evidence of any extraterrestrial life.
Extraterrestrial life is defined as life that does not originate from Earth. Life on other planets is a simpler way to word it. Aliens on other planets is an example (but I doubt aliens live on other planets) of extraterrestrial life. Also, bacteria are another example. There is proof that there was once water on Mars, and that there may have been bacteria living in that water. That bacteria would also be considered as extraterrestrial.
Extraterrestrial life.
This field is called "exobiology".
Nope. Unless exobiology is correct, in which case we're all extraterrestrial. no