People often think of Earth as a gigantic sphere. But, in fact, its shape is more like a squished ball that bulges out at the equator –– an imaginary line around the middle of the planet, exactly between the North Pole and the South Pole.
This ‘bulge’ is caused by the Earth’s spin and the effect of ‘gravity‘. Gravity is an invisible force that attracts objects towards each other. It’s this force that pulls things towards the Earth and stops us floating off into space!
The Earth’s diameter (distance straight through the middle) measures a huge 12,800 kilometres, making it the fifth largest planet in the solar system. Jupiter, Saturn, Uranus and Neptune are even bigger!
The ladybug lifecycle begins when a batch of bright-yellow eggs are laid on branches near food sources. They hatch as larvae in four to 10 days and then spend about three weeks feeding up—the earliest arrivals may eat some of the eggs that have not yet hatched. Once they're well-fed, they'll begin to build a pupa, and after seven to 10 days they emerge as adults. The insects typically live for about a year.🐞
Earth is the only planet in our solar system known to support life. This is because it has two very important things that living creatures need to survive –– lots of oxygen and lots of water! Its distance from the sun means it’s not too hot and not too cold for creatures to live on, too.
Earth’s ‘atmosphere’ is also hugely important for sustaining life. The atmosphere is a huge blanket of gases – mostly oxygen and nitrogen – wrapped around Earth, protecting our planet from the sun’s strong rays. At the same time, the atmosphere helps keep the Earth’s temperature comfortable for living beings – and it protects us from meteors, too!
The Sun is what is known as a main sequence star; that is, a sphere composed primarily of the two gases hydrogen and helium such that certain conditions are met.
The first condition is that it must have a mass falling within a certain range. Though debated, this range is generally accepted to be between approximately 1.4 x 1029 kg and 3.0 x 1032 kg. (This range is often describe as at least 75 times the mass of Jupiter and no more than 150 times the mass of the Sun itself.)
The second and most important condition is that nuclear fusion must be present. Nuclear fusion is the process whereby two lighter atomic nuclei join or “fuse” together to produce a heavier atomic nucleus. In the context of stars, hydrogen is the lighter and helium the heavier.