About 2 000 years ago, who proposed the idea of geocentric?

What is geocentric?

Who proposed the idea of heliocentric model in the 1500's?

What is a heliocentric model?

When was the telescope invented and why?

What is spectroscopy?

What are astronomical units?(AU)

What is a light year?

What is a nebulae?

What are terrestrial planets and what are they made up of?

What are our terresteial planets and what are they made up of?

What are our Jovian planets and what are they made up of?

What is a meteorite?

A comet is...

Difference between a lunar eclipse and a solar eclipse?

Fun fact

Microgravity is...

Fun fact

What is optical interferomety?

A radio telescope is...