2007-02-05 00:34:39 · 3 answers · asked by roland 1 in Science & Mathematics ➔ Astronomy & Space
Currently the knowledge about the planets are adquired mainly by the spacecrafts sent as probes. They take photos at close distances and they measure a lot of other characteristics, such the magnetic field around the planet, the composition of the atmosphere and, as is the case for Mars, their ground composition.
There is also theory behind, to know the probable composition of their nucleus, etc.
That about the planets of our solar system.
For exoplanets, that are planets of other stars (we know about two hundred of them) we just know their existence, from the irregularities they impress on the movemente of their main star.
2007-02-05 00:45:45 · answer #1 · answered by Jano 5 · 1⤊ 0⤋
It was by telescopic observation mainly, but now automated probes like Voyager have been sent to all the planets, some actually landing and performing tests.
2007-02-05 00:42:12 · answer #2 · answered by CLICKHEREx 5 · 0⤊ 0⤋
We can observe the plants. Through telescopes, and we can test the planets with space craft or instruments that can measure different items on the planet.
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2007-02-05 01:24:22 · answer #3 · answered by Bacchus 5 · 0⤊ 0⤋