Because they're extremely far away, and they're almost impossible to see visually because the star itself blocks out any light reflected by those planets. However, it is possible to detect them. One simple way is by seeing how the star's light diminishes when one or more of those planets pass in front of them. Or, if their orbits aren't lined up right for us to observe this, we can detect the subtle gravitational "wobble" caused by the presence of those planets. It's a difficult and time-consuming process, but it has paid off - we now know of hundreds of these "exo-planets."
Extra solar (or Exo) planets are planets that do not orbit the Sun. Planets in our solar system orbit the Sun.
neptune
The surprising thing to me is how MANY extra-solar planets have been discovered. Considering the limitations of the Kepler Space Telescope's design, this indicates that there may be planets around a majority of the stars.
Scientists are currently using mirror telescopes in space that do not have to deal with light pollution and are more clear than lens telescopes to take pictures of the solar system. They are also using radio telescopes to try and discover extra terrestrial life.
If you are talking about Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, these planets all orbit the Sun.It wasn't very long ago that these were the only planets we knew about. But with the development of enormously powerful space telescopes and newer more powerful computers, scientists have now discovered over 300 "extra-solar planets"; planets that orbit other stars. We've discovered so many, so quickly, than we now need to revise our theories on how planets form. We used to think that planets would be rare; now, it looks like a majority of mid-sized stars will have planets.
extra solar planets are not bright compared to the stars they orbit
Extra solar planets are planets that is outside of our solar system.
Astronomers believe that planets orbiting other stars, known as exoplanets, are common in the universe. They have been detected using various methods such as the transit method and radial velocity method. The discovery of exoplanets has greatly expanded our understanding of planetary systems beyond our own.
No Earth-like planets have been discovered yet, but our best telescopes are (so far!) incapable of locating any extra-solar planets that small. With the launch of the James Webb Space Telescope, this may change.
Extra solar (or Exo) planets are planets that do not orbit the Sun. Planets in our solar system orbit the Sun.
Eight
I'm not sure that carbon dioxide is very useful, but oxygen certainly is. Oxygen would strongly indicate the presence of life! I mean a significant amount of oxygen, of course.
Fomalhault
yes, for example us and the rest of the planets in the solar system. to date there are also approx 400 extra solar planets discovered (planets beyond our solar system)
extra terestrial is life on other planets.. so no
Inner planets
They have been searching for evidence using a complex sound system to listen for radio waves from extra terrestrial intelligence.