Pluto was discovered by Clyde Tombaugh in 1930 Percival Lowell made calculations on the orbit of Neptune and predicted a 9th planet. His calculations were based on flawed data, there is no 9th planet.
Pluto and Charon are tidally locked on each other Just as we only see one side of our moon from Earth, Pluto only sees one side of Charon. Since Pluto is also tidally locked, Charon also only sees one side of Pluto.
Ceres has been promoted from asteroid to dwarf planet Ceres was called a planet when it was discovered in 1801 but it was later demoted when we started to find lots of other objects in the asteroid belt
The Debris of the Solar System Asteroids and comets are leftover planetesimals. We don’t see the icy planetesimals until the fall in to the inner part of the system solar
When a piece of an asteroid comes close to Earth it may become a meteor
Meteoroids, Meteors and Meteorites NEO 1994 XM1 Leonid Meteor Shower
Big rocks DO fall from the sky! Fortunately for us, they don’t do it too often
The impact released trillions of tons of CO2 into the atmosphere The crater is buried several hundred meters under the surface and is over 200 km in diameter
Fortunately, most impacts are small The Peekskill meteorite fell in 1992 and hit an 1980 Chevy Malibu. Insurance wouldn’t pay for the damage but she got $10k for the car and $69k for the meteorite from a collector.
The most common meteorite, stones look like ordinary rocks with burnt crust
Widmanstätten Patterns are iron crystals that take millions of years to form The iron has to cool from the molten state at no more than a few degrees every million years to form these crystal patterns
Carbonaceous chondrites are from the earliest age of the solar system They show the original condensation grains from the solar nebula period when they formed
The different types of meteorites implies different types of parent asteroids Some asteroids have a lot of carbon materials. These are known as C-type asteroids
To form S-type and M-type asteroids a larger body must be smashed to pieces
Asteroids tumble Most have rotational periods of 9 to 10 hours
Some asteroids are piles of debris 253 Mathilde
Many comets come from the Kuiper Belt The Kuiper Belt is a thick donut shaped region extending from about 30 AU out to 50 AU. Pluto and Eris are the largest known Kuiper Belt objects
Some comets come from the Oort Cloud The Oort Cloud may extend out to a lightyear (50,000 AU) from the Sun
A comets tail always points away from the Sun There are two tails: a dust tail that trails behind some and an ion tail that always points directly away from the Sun
Comets “die” in one of three ways 1: They fall in to the Sun They don’t have to actually fall into the Sun, just get close enough to burn up
2: They collide with a planet or moon Shoemaker-Levy 9 had a amazing collision with Jupiter in 1994
Will a comet ever hit us? The highest rated object is rated a little below 1
We were probably hit by a fragment of a comet in 1908 The Tunguska event flattened over 800 square miles of forest in Siberia. It was probably an object about the size of a football field that exploded about five miles above the surface