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How do we discover planets light years away?
Until around 2012, the radial-velocity method (also known as Doppler spectroscopy) was by far the most productive technique used by planet hunters. Planets of Jovian mass can be detectable around stars up to a few thousand light years away. This method easily finds massive planets that are close to stars.
How do scientists find out about the planets?
Probes, such as NASA’s Cassini probe, have been sent to explore other planets. Thanks to the Kepler telescope, launched in 2009, scientists now know that there are possibly over 3,000 planets orbiting more than 2,000 stars in the Milky Way galaxy.
How can we find Earth like planets in other solar systems?
Astronomers have discovered far more planets outside our solar system, known as extrasolar planets, than within it. Astronomers can not only detect a planet’s presence, they can deduce a lower limit to its mass and distance from its parent star, and the length of its year.
How far away are the planets we have detected?
We haven’t detected planets millions of light years away. Right now the most distant is less than 20,000 light years away. Even for the planets we have detected, they are for the most part not “seen” or imaged directly. Instead they are found by the effect they have on the parent star (usually gravitational wobble or transit detection).
Why can we see exoplanets thousands of light years away?
The reason why we can see exoplanets thousands of light years away but not a planet 200 AU away (about 30 light-hours) is because these planets are found using different techniques.
Why are planets so hard to find in our Solar System?
Planets far from any star have little gravitational effect and only tiny amounts of reflected light. Such objects are difficult to find in our system and are currently well beyond detection in other systems. Pretty simple reason really. We only see exoplanets under extremely lucky circumstances.
How do we detect planets outside our Solar System?
Other detection techniques for planets outside our solar systems include: measuring the wobble of a star due to a planet’s gravity pulling on it. directly imaging the planet with a high-resolution telescope like the Hubble Space Telescope.