Category Astronomy

The Solar System is located in the Milky Way, a huge spiral galaxy containing billions of stars. They are grouped in “arms” that spiral outwards. All of the stars are travelling around a point at the centre. Scientists think there is a supermassive black hole located there that sucks in anything that gets too close to it.

The night sky

On a clear, dark night it is possible to see the Milky Way stretching across the sky at night, cloudy band. Although the Milky Way is a spiral galaxy, it doesn’t look like it from Earth because we are inside it!

Black hole

The pull of gravity from a black hole is so great that not even light can escape it. Supermassive black holes, like the one at the centre of the Milky Way, also fire out jets of energy.

 

Picture Credit : Google

The Solar System is made up of our star, called the Sun, and everything that travels, or orbits, around it. This includes eight planets and their moons, dwarf planets, asteroids, comets, and smaller bits of rock and dust. The Solar System is one of many solar systems that exist in the Universe.

Asteroids

Asteroids are lumps of rock and metal left over from when the Solar System first formed. Most can be found in the asteroid belt, which is located between the planets Mars and Jupiter.

Gas planets

The four outer planets – Jupiter, Saturn, Uranus and Neptune – are the largest planets in the Solar System. They are mostly made of gas and spacecraft are unable to land on them.

Rocky planets

Closest to the Sun are the four rocky planets – Mercury, Venus, Earth, and Mars. They all began their existence in the same way, but over time became very different worlds.

Dwarf planets

Dwarf planets, such as Pluto, also travel around the Sun. These worlds are smaller than the other planets. Scientists think there may be dozens of undiscovered dwarf planets hiding in the Solar System.

Super-sized

The Solar System is so big that if the Sun were the size of a basketball, the Earth would be the size of a sesame seed – and it would be located more than 25 m (80 ft) away!

 

Picture Credit : Google

The biggest planet in the Solar System is Jupiter. But the title for the second biggest planet in our Solar System goes to Saturn.

Since Saturn is so big, but has so little mass, it has a very low density. In fact, if you had a pool big enough, Saturn would float. The density of Saturn is less than water. And this means that you wouldn’t experience a lot of gravity if you tried to walk on the “surface of Saturn”. If you were standing on the surface of Saturn (I know, that’s impossible), you would experience only 91% the force of Earth’s gravity.

If you wanted to compare Saturn to Earth, it’s 9.4 times as big as the Earth, and 95 times as massive. It was just a hollow shell, you could pack 763 Earths inside Saturn, with a little room to spare.

 

Picture Credit : Google

The Sun won’t last forever. Just like other stars in the Universe, the Sun was born and it will die. At 4.6 billion years old, the Sun is almost halfway through its life. In about 5 billion years time it will start to change, as it burns up the fuel that kept it shining bright for so long. It will expand to become a type of star called a red giant, before shrinking to become a white dwarf.

Life of the Sun

The Sun is a medium-sized star. The Sun was born in a nebula – a giant cloud of gas and dust. The Sun is currently middle-aged. It is about halfway through its life. As it runs out of fuel, the Sun starts to collapse, but this causes it to heat up again. The outer layers of the Sun expand to turn it into a red giant. The Sun throws off its outer layer of gas and dust. The Sun will spend its final days as a white dwarf, a star about the same size as Earth.

Eating Mercury

The red giant Sun will become so enormous that it will gobble up the planet Mercury!

 

Picture Credit : Google

It is one of the great unanswered questions. Some scientists think it is very likely that the Universe is full of life. Their motto is “follow the water”, as they believe the best place to find life will be where there is liquid water. Within our own Solar System there are several places of interest to these scientists.

Candidates for life

Although finding intelligent life, like us, in our own Solar System is unlikely, there are words that may be home to simple forms of life. Scientists are interested in these places because they have conditions that might be suitable for life to exist.

Europa

Scientists believe that there is a liquid water ocean under the thick frozen surface of Jupiter’s moon, Europa. Life has been found at the deepest, darkest parts of Earth’s oceans, and scientists think the same thing might be possible on Europa.

Mars

Mars is of interest to scientists because of the recent discovery of flowing water on its surface. It is possible that life may have existed on the planet in the past, or that some form of life may still exist today.

Enceladus

Enceladus is a moon that orbits around Saturn. It has a frozen surface and scientists think there is liquid water underneath. The Cassini spacecraft has been flying through geysers of frozen water that erupt from the surface, and analyzing it to see if it could harbor life.

Titan

Titan is Saturn’s largest moon. It has a thick atmosphere and seas made of liquid gas. Titan is very interesting may be similar to that of the early Earth – before life emerged on our planet.

SETI Institute

SETI stands for “Search for Extra Terrestrial Intelligence”. The SETI Institute, based in California, USA, is looking for evidence of life in the Solar System and the wider Universe. SETI scientists try to find places that may have the ingredients needed for life and also listen out for possible signals that may have come from aliens. SETI believe our first contact with intelligent life in the Universe may even be with robots built by alien civilizations!

 

Picture Credit : Google

Did you know that you are a different age on each planet? This is because a year is the time it takes an object in the Solar System to orbit the Sun. every planet or dwarf planet takes a different length of time to do this, so their years can be long or short. A year on Earth is the same as about four years on Mercury, while a year on Pluto takes 248 Earth years!

Mercury

Mercury flies round the Sun more quickly that the other planets – its year is only 88 Earth days long. That means that if you are 10 on Earth, you are 41 on Mercury!

Venus

A day is the amount of time it takes a planet to spin once. Venus takes 225 Earth days to orbit the Sun, but it spins very slowly. This means the days on Venus are very long. In fact, a day on Venus is longer than a year on Venus!

Pluto

Pluto is so far from the Sun that you would wait a long time for your first birthday. It would take 2,480 Earth years to turn 10!

Neptune

A year on Neptune takes 165 Earth years. This means that it is impossible to turn one on Neptune in a human lifetime.

 

Picture Credit : Google