Life Elsewhere
Astrobiologists believe that three ingredients which are vital for life. They are water, energy, and organic molecules such as carbon (C). Energy and organic molecules are abundant in the Universe. But liquid water is rare.
- The Habitable Zone (HZ)
A habitable zone (HZ) is the area around a star where liquid water could exist on or near the surface of a planet. We call it an HZ because we believe liquid water is vital for the existence of life.
An HZ is sometimes called a CHZ, where the C stands for 'continuously' or 'circumstellar'. The name Goldilocks Zone is perhaps a more useful way to describe an HZ. It is a region that is not too hot, and not too cold, but just right! The size and location of an HZ depend on the size and type of the star.
Understanding the Solar System
After the invention of the telescope, everything changed for astronomers. They were now able to see many more objects in the night sky. These faint objects were either small, or far away, or both!
In 1781, William Herschel became the first person in thousands of years to discover a planet. He used a telescope he had built himself and found the 7th planet, Uranus. A few years' later in 1845, Neptune was found by both British and French astronomers. Both groups had watched the orbit of Uranus and used their data to predict there was an 8th planet. They worked out where it would be and when they looked, there it was!
Claudius Ptolemy
Occupation
Mathematician, Astronomer, Geographer
Year born
100 AD
Research Areas
Movements of planets and stars, Cartography
- Early Life
Claudius was born in Alexandria, Egypt, which was part of the Roman Empire at the time. Very little is known about his life. The information we do have has been taken from the books he wrote.
Edmond Halley
Occupation
Astronomer, Mathematician
Year born
1656
Research Areas
Comets, Transits, Stars, Maths, Geophysics
Nicolaus Copernicus
Occupation
Astronomer, Mathematician, Clergyman
Year born
1473
Research Areas
Planets, Mechanics
- Early Life
Nicolaus was born in Thorn, Poland. His father, who sold copper, died when Nicolaus was 10. After his father's death, Nicolaus’ uncle looked after him and made sure he had a good education.
When he was 23, Nicolaus went to Italy to study law. In Italy, he stayed with a maths professor and became interested in astronomy.
Distances in the Solar System Poster
How far apart are the planets in the Solar System. The answer may surprise you!
The distance between the planets in our Solar System is not regular. The inner 4 rocky planets are spaced much more tightly than the outer 4 giant planets.
Download, print and display this free poster!
Planet Facts Posters
Do you know how many planets in our Solar System have rings? Or how many have moons? Learn some interesting facts about the planets in our Solar System with these free printable posters!