The solar system pt 2 MR. BANKS 8 TH GRADE SCIENCE

Transcription

1 The solar system pt 2 MR. BANKS 8 TH GRADE SCIENCE

2 Dwarf planets Following the discovery of multiple objects similar to Pluto (and one that was even bigger than Pluto) a new classification for planets was created. 1. The object must be in orbit around the Sun. 2. The object must be massive enough to be a sphere by its own gravitational force. 3. It must have cleared the neighborhood around its orbit. There can t be any other large objects near the path the planet orbits in.

3 Dwarf planets There are currently five confirmed dwarf planets Pluto, Ceres, Haumea, Makemake, and Eris There are an estimated 200 dwarf planets in the area near Pluto, and as many as 10,000 dwarf planets orbiting the sun at extreme distances.

4

5 Pluto The first dwarf planet discovered. Pluto is small, about 2/3 the size of our moon. We know little about Pluto, it is likely rocky and very cold. It has five moons the largest, Charon is about 1/10 the size of Pluto itself.

6 Pluto Pluto has a very odd orbit compared to the other planets, another reason it didn t make sense to include it as a planet.

7 New horizons A space probe launched in 2006 on a mission to investigate Pluto. It has also investigated an asteroid and Jupiter on the way.

8 The dwarf planets Eris The largest dwarf planet, ¼ the size of Earth. Takes 558 years to orbit the sun. Haumea Has two moons, observations of telescope images suggest that Haumea is an ellipsoid. Makemake Not much is known about it besides that it is about 2/3 the size of Pluto.

9 Ceres The largest object in the asteroid belt between Mars and Jupiter. There are a pair of bright spots located in a crater, it s not clear what they are. It accounts for 1/3 of the total mass of the asteroid belt. Ceres has a thin dusty outer layer over a layer of water ice with a rocky core. The Dawn space probe entered into orbit on April 24 th and should help gather more info on Ceres.

10 Comets A small object orbiting the sun in an elliptical orbit. When it passes close to the sun, the comet heats up and the materials that make up the comet begin to escape out into space. The materials are blown away in the solar wind and from a stream of visible particles known as the tail of the comet. This can include water, carbon dioxide, methane, ammonia or even rock dust.

11 Rosetta Launched in Investigated several asteroids before achieving successful orbit around the comet 67P.

12 Asteroids Also known as minor planets or planetoids. Defined as anything above a certain size that isn t rounded like a planet and isn t a comet. Can range in size from 1,000 km to 10 m. Generally composed of rock and ice.

13 Meteors A small rocky or metallic object traveling through space. They range in size from a grain of sand to 10 meters wide. Most are fragments that have broken off comets or asteroids. Meteors that enter Earth s atmosphere are the shooting stars seen at night.

14 Meteors As they fall through the atmosphere, friction from air molecules heat the surface of the meteor and melt/break it apart. What lands is only a small fraction of the original object. In space they are known as meteoroids. When falling through the atmosphere they are meteors. And on Earth they are meteorites.

15 The asteroid belt A region of space roughly between Jupiter and Mars that is occupied by millions of asteroids. We ve identified hundreds of thousands. Over 200 are greater than100 km wide. Collisions between asteroids happen frequently (on an astronomical time scale) with large asteroids colliding about every 10 million years.

16 The Kuiper belt Similar to the asteroid belt in that it contains large numbers of small objects. However it is far wider and there are much more massive objects located there. All the known dwarf planets besides Ceres are located there. It extends from the orbit of Neptune outward another 1,800,000,000 miles.

17 The Oort cloud A theoretical sphere of icy bodies that extends out far away from the Sun, as far as 2 light years. Studies of comets and their orbits have given rise to the hypothetical existence of this region. The Oort cloud comprises the theoretical extent of the gravitational influence of the sun. None of our current probes will reach what is thought the be the outer edge of the cloud before their batteries run out.

18

19

20