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Period: 200 to
Astronomy Timeline
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Kepler sees a supernova
It is the most recent supernova to have been unquestionably observed by the naked eye in our own galaxy, occurring no farther than 6 kiloparsecs or about 20,000 light-years from Earth -
Galileo observes Earths Moon
Galileo found that the Moon had mountains, valleys, and plains like the Earth. -
Kepler discovers laws of planetary motion
Kepler discovers the shapes of planetary orbits, how the speed of a planet varies as it orbits the Sun, and the relationship between orbital distance and orbital period -
The discovery of Uranus by Herschel
The planet Uranus is a gas giant like Jupiter and Saturn and is made up of hydrogen, helium, and methane.
The third largest planet -
Pierre Simon Laplace proposes stars can produce black holes
Laplace proposed that if a star is so compact that its escape velocity exceeds the speed of light, then not even light can escape from the star and then becomes a black hole sucking in everything near unknown where it goes. -
The first measurement of the distance to a star is made by Bessel
Bessel had to measure the separation between the stars in the field of his telescope that was only 0.00001742° or less than two hundred thousandths of a degree comparable to the width of a pizza. -
Discovery of Neptune
Neptune was the first planet to get its existence by mathematical calculations before it was seen by a telescope.
Alexis Bouvard led the discovery. -
Clyde Tombaugh discovers Pluto
Tombaugh discovered Pluto by comparing photographic plates taken of the same region of the sky about a week apart.
At the time of its discovery, Pluto was considered to be the ninth planet in the solar system.
Plutos surface is expected to be made up of mostly ice and rock because it is so far away from the sun.
It has recently been deleted as a planet and named a "dwarf planet" -
S. Chandrasekhar shows white dwarf stars are made of degenerate electrons
Stars made up of degenerate electrons are the example of Chandrasekhar limit which is the mass above which electron degeneracy pressure in the star's core is insufficient to balance the star's own gravitational self-attraction.
White dwarfs with masses greater than the limit undergo further gravitational collapse, making them into a different type of "stellar remnant", such as a neutron star or black hole.
Stars with masses under the limit remain stable as white dwarfs -
Apollo 17, last Apollo mission to Moon
Apollo 17 astronauts traversed the greatest distance using the Lunar Roving Vehicle and returned the greatest amount of rock and soil samples.
Eugene Cernan, commander of Apollo 17, still holds the distinction of being the last man to walk on the Moon
No humans have visited the Moon since December 14, 1972. -
Charon, the moon of Pluto, is discovered.
Plutos largest moon
Charon's volume and mass allow calculation of its density from which it can be determined that Charon is largely an icy body and contains less rock by proportion than Pluto -
Hubble Space telescope launched
Hubble's orbit outside the distortion of Earth's atmosphere allows it to take extremely sharp images with almost no background light. Hubble's Deep Field have been some of the most detailed visible-light images ever, allowing a deep view into space and time. Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe.
Hubble is one of the largest and most versatile, and is well known as both a vital research tool and a -
Galileo obtains first up-close images of asteroid (Gaspra)
Flyby of Gaspra occurred on 29 October 1991 at a distance of about 16,200 km.
This picture of asteroid named Gaspra is a combination of the highest-resolution morphology taken by the Galileo spacecraft
Gaspra is an irregular body with dimensions about 19 x 12 x11 kilometers -
The comet Shoemaker Levy 9 strikes Jupiter
Pieces of an object known as Comet Shoemaker-Levy 9 collided with Jupiter.
This is the first collision of two solar system bodies ever to be observed, and the effects of the comet impacts on Jupiter's atmosphere have been a cool site to see -
Pluto is no longer a planet, now it is a Kuiper belt object
In the late 1970s, following the discovery of minor planet 2060 Chiron in the Solar System and the recognition of Pluto's relatively low mass, its status as a major planet began to be questioned.
Originally classified as the ninth planet from the Sun.
