The exact number is not known. But it does seem that most stars have at least one planet, and probably several planets, at least on average. Not even the number of stars in the immediate neighborhood can be known for sure, since red dwarves are quite hard to detect.
Here is an estimate. The Wikipedia article on "List of nearest stars" lists 56 hydrogen-fusing stars at a distance up to 5 parsec, or 16.3 light-years. Assuming the density of stars is more or less constant at distance up to 100 light-years, that would mean that for a volume 231 times larger (up to 100 light-years), there would be about 12,930 stars. Assuming that each of them has 1-10 planets on average, and doing some rounding, that would mean there are between 13,000 and 130,000 planets at that distance. Please note that despite the fairly large range, there is still a lot of guesswork involved.
All of them in our solar system, plus all others within a distance of about 100 to 120 light years from us.
Exoplanets are planets that orbit a star outside of our solar system, while other planets refer to those within our solar system, such as Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Exoplanets are located in other star systems, light-years away from Earth, and have different characteristics compared to the planets within our solar system.
Because planets are rather small on astronomical scales - or at least, when compared to stars, and not luminous like stars, it is very hard to see them at great distances. NASA's Kepler spacecraft, which was launched to detect planets within habitable zones of stars, detected in 2011 a couple planets orbiting a star roughly 1000 light years distance. The planets, designated Kepler 20e and 20f, are part of an unusual solar system, and are roughly Earth-sized and 'rocky' but orbiting their host star within the distance of Mercury to our Sun, which would make them too hot for life.
No two planets within our solar system have the same exact size. However, Earth and Venus are quite close - their diameters differ by only 652km.
The Kepler Satellite has discovered well over a thousand planetary candidates, via transit. Kepler-10 b is 173 parsecs (564 light years) while Kepler-35(AB) b is 1645 parsecs (5365 light years). Kepler 42 b, c, & d are 38.7 parsecs (126 light years). This satellite is not a planet, but rather an artifact orbiting our sun at about the same distance as the Earth, built to detect exoplanets. Exoplanets are planets that orbit stars beyond ours.
Light years are used to measure distance from Earth to distant stars and planets.
4.2 light years is the distance to the Alpha Centauri Star System.
All of them in our solar system, plus all others within a distance of about 100 to 120 light years from us.
Exoplanets are planets that orbit a star outside of our solar system, while other planets refer to those within our solar system, such as Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Exoplanets are located in other star systems, light-years away from Earth, and have different characteristics compared to the planets within our solar system.
Because planets are rather small on astronomical scales - or at least, when compared to stars, and not luminous like stars, it is very hard to see them at great distances. NASA's Kepler spacecraft, which was launched to detect planets within habitable zones of stars, detected in 2011 a couple planets orbiting a star roughly 1000 light years distance. The planets, designated Kepler 20e and 20f, are part of an unusual solar system, and are roughly Earth-sized and 'rocky' but orbiting their host star within the distance of Mercury to our Sun, which would make them too hot for life.
Yes. Anything within 25,000 light years is within our Galaxy.
Every planet in the Solar System is closer than one light year to the Earth. In fact, when you travel at the speed of light on January first departing from our own star (the sun) it is still January first when you pass Pluto...
that remains to be seen. although the chances are slim, there might be an earth-like planet millions of light-years away!
The distance from the Earth to Saturn varies - depending on whether both planets are on the same or opposite sides of the sun. At their nearest the distance is approx 0.000127 light years.
No two planets within our solar system have the same exact size. However, Earth and Venus are quite close - their diameters differ by only 652km.
Nebulae can vary in distance from Earth. Some are close, within a few hundred or thousand light-years, while others can be many thousands or even millions of light-years away. The closest known nebula to Earth is the Helix Nebula, which is about 700 light-years away.
How many light years away is Jupiter from Earth when there closest?