The Solar System

It appears to us that the Earth is at the centre of the universe and this was believed by most people until about 1700. Copernicus first published a new model with the Sun at the centre in about 1500 and this was taken up by Galileo in about 1600.

Galileo had a famous dispute with the catholic church authorities that ended with him having to retract after being put in court and challenged to prove his assertion, which he was unable to do.

But after new scientific discoveries by Isaac Newton and others it became more and more clear that having the Sun at the centre provided an easier and simpler model. Finally in the 19th century Bessel discovered that the nearby star 61 Cygni moved slightly forward and back every six months, in time with the Earth's movement around the Sun, and this was the final demonstration of the Earth's orbital motion.

The movement was extremely slight because even the near stars are extremely remote, and it it was not until Bessel's time that observational techniques became sufficiently sensitive to detect it.

Therefore now it is believed that the Sun is at the centre, not the Earth.

He didn't know it, he just brought out a new theory that showed that with the Sun at the centre the planets' paths could be explained more simply.

That was in 1543 and Kepler produced another heliocentric theory in 1609 which had the planets moving in elliptical orbits round the Sun.

The only thing in favour of Kepler's theory at the time was that it explained the planets' positions more accurately than previous theories. But 80-90 years later Newton's discoveries in gravity and the laws of motion were used to prove by theory that the planets must move in elliptical orbits.

The planet Mercury completes one revolution in its orbit around the Sun in about 88 Earth days (87.969 days, to be more exact). This is about 0.241 Earth years.

It's your solar system too.

Well we can use maths to work out how long it would take certain things in our and other solar systems to form, and by using models and simulations coupled with the laws of physics.

Olympus Mons, on Mars

No.

The contents of the early universe had no heavy atoms, just Hydrogen and Helium (maybe some Lithium but really little proportionally) and very little else.

Heavier elements are created in the explosions of stars, the bigger the star the heavier the elements that can be created from lighter elements.

So no Earth-like planets could coalesce without several genertions of stars to make enough heavy elements like Carbon, Iron, Gold, etc. that we find on Earth. I have heard that we are dust of the nineteenth generation of stars.

The Greek philosopher Aristarchus of Samos is credited with first questioning the geocentric theory in the 3rd century BC. He proposed a heliocentric model in which the Earth and other planets revolve around the Sun.

The first planet in the solar system is Mercury

The Sun travels at 600,000 miles per hour and has a fixed circuit to follow which would take 200 milliion years at that pace to complete. Scientist recently found that out, however, the Bible said so 1500 BC, in the book of Psalm 19:5,6. (Even though around 1500BC it was believed that the earth sat on a large animal or a giant ... the Bible said otherwise). "The school of Biblical Evangelism"

Photosynthesis stops. If it stops long enough, the plant dies.

No, Uranus is not the 2nd largest planet but the third largest planet. Saturn is the second largest planet in the solar system after Jupiter.

Uranus is 3rd largest by diameter, but 4th most massive. (Neptune is slightly smaller but denser than Uranus.)

Precession, which in this case refers to a movement of Earth's axis. A full "turn" takes about 26,000 years.

One recent hypothesis is that after the earth cooled enough for water to stay liquid, comet impacts provided all of earth's current water and its original methane, ammonia, nitrogen, carbon dioxide atmosphere. That would take a lot of impacts. All of these were long before there was anyone to name them.

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He believed that everything rotated around the sun. Also, he believed that the planets orbit were not circular, they are oval. He was a catholic, but they didn't like him because he was going against the church with what he believed.

Ptolemy's research in the field of astronomy led him to continue down the vein of other Greek scholars who believed in the Geocentric system of planetary orbit. The Ptolemaic system, which believed that the planets and sun moved in small mini-orbits, known as epicycles, within a larger, greater orbit around the earth, was comprised in order from closest to farthest as Mercury, Venus, Sun, Mars, Jupiter, and Saturn. Due to this system's ability to fairly accurately predict the paths of the observable planets in the sky, it remained widely accepted until Copernicus became champion, if you will, of the Heliocentric theory. Even then, Ptolemy's system was still better able to explain the motions of the planets. It was not until the later addition of Kepler's laws of motion that the Heliocentric theory fell neatly into place.

It has been suggested that comets originate in the Oort cloud and then travel in long elliptical orbits around the Sun.

Possibly you're looking at a lunar eclipse. I don't see any on the schedule but that's normally what causes it. The moon goes into the Earth's shadow first the preumbra and then the umbra. When it does only the red part of the sun's spectrum of light is bent by the Earth's gravity enough to hit the moon. So the moon looks red.

Telescopes were first and foremost. We have extended the range of these into both the ultraviolet and deep infrared, and built giant radio telescope arrays as well.

Robotic missions have given us close up views of more remote regions of the solar system, such as the surfaces of Venus, Mars, & Titan.

Most recently two gravitational wave detectors, the LIGO facilities, have come on line.

The solar system formed from a rotating cloud of gas and dust, which led to a counter clockwise rotation due to the conservation of angular momentum. This rotation direction has been maintained over billions of years due to the lack of significant external forces to change it.