Flashcards in Astronomy Deck (13)
What are the planets in our solar system (in order from closest to the sun to the farthest away from the sun)
How many planets are there in our solar system?
What is the smallest planet?
What is the largest planet?
What is the definition of a planet?
A celestial body that:
1). is in orbit around the sun
2). has cleared its orbit.
3). has sufficient mass for its self-gravity to assume a round shape
A celestial body that was considered a planet until 2006, when it was reclassified as a dwarf planet because:
- it has only cleared a third of its orbit around the sun from the time when it was discovered until now.
- The sun is the star at the center of our solar system.
- the planets all orbit around it
What is the sun composed of?
Hydrogen and helium.
The Milky Way is our galaxy.
- It contains at least one black hole called Sagittarius A.
- it is part of a larger group of about 50 galaxies called the Local Group.
When did the Milky Way begin forming?
Roughly 12 billion years ago
Action of the Milky Way
The Milky Way is constantly growing by merging with other galaxies.
- The Milky Way is slowly moving through space and gobbling up stars.
- right now it is acquiring a small galaxy called the Sagitarius Dwarf Spheroidal.
Closest galaxy to the Milky Way.
- it will collide with the Milky Way in 4.5 billion years and create one giant galaxy.