Category The Solar System

Do all the planets and their moons have active volcanoes?

For many years, scientists believed that Jupiter’s moon lo was geologically dead. This means it didn’t have things such as earthquakes, newly forming mountains or volcanoes. However, it turns out the scientists were wrong about lo. In 1979, when NASA’s Voyager 1 spacecraft took close up pictures of lo, the pictures showed a massive plume erupting from lo’s surface into space. That’s when they realise that lo did not just have volcanoes, it had active volcanoes. And, lo was no longer considered geologically dead. When these pictures were taken it was the first time an erupting volcano was found anywhere other than Earth. So that leaves us wondering, do all the planets and their moons have active volcanoes? Let’s take a look

Mercury: The planet once had active volcanoes, but not anymore. Scientists believe violent volcanic eruptions that shaped Mercury’s surface, likely ended about 3.5 billion years ago.

Venus: Venus, on the other hand is covered with volcanoes. The hottest planet in our solar system has over 1,000 volcanoes, including some that might still be active, according to what scientists think.

Mars: Mars is home to Olympus Mons, the solar largest volcano in our system. It is also the mountain in our solar largest led our solar system Mars is filled with tall volcanic mountains, and while scientists haven’t seen an eruption on Mars, they think there could be some in the future.

Jupiter: Scientists have found volcanoes and observed volcanic activity only on lo, Jupiter’s moon. Eruptions from lo’s volcanoes are so massive that it can been seen by a spacecraft that is pretty far from lo.

Saturn: Saturn’s moon Enceladus has cryovolcanoes. These volcanoes are similar to regular volcanoes, except they spew water and other gases like geysers.

Uranus: Since it is a gas planet, it does not have any volcanoes.

Neptune: While Neptune doesn’t have volcanoes as it is a gas planet, its frozen moon, Triton, has cryovolcanoes that are active.


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How did scientists estimate Sun’s age?

The Sun’s age

Scientists say our Sun is four-and-a-half billion years old but how did they estimate its age?

To predict the age of the Sun, scientists looked at the age of the whole solar system because it all came together around the same time.

To find out the solar system’s age, scientists looked for the oldest things they could find. And, Moon rocks, meteorites and Earth rocks worked perfectly well for this. Scientists extensively studied these objects, and after much research came to the conclusion that each of the objects were approximately four and- A-half billion years old, and hence, the Sun is likely to be of the same age.

How long will it shine?

Now that we know how old the Sun is, how much longer will it shine upon us?

Scientists believe that stars such as our Sun usually burn for about nine or 10 billion years. This means our Sun is halfway through its life and will last for another five billion years at least.

Once five billion years are up, the Sun will become a red giant. The Sun will become bigger and cooler at the same time and it will be a lot different than the Sun we know today. As a red giant our Sun will become 2,000 times brighter than it is now. Wonder what would happen to our solar system at that time – will there be new life?


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If fire needs oxygen, where does the sun get oxygen if there’s no oxygen in space?

Indeed, this was a scientific problem for hundreds of years: if Sun consisted of oxygen, it would run out of fuel in a few hundred years. So what’s the deal?

But wait, nowadays we know more. What other objects glow like the Sun, even without oxygen?

This example of a lamp bulb shows that not all objects that shed light need oxygen to do so. Of course, for light bulb that gas is typically some inert gas (see e.g. Which gas is typically used in light bulb?).

In fact, the light bulb doesn’t use up the gas. Instead, it uses an electric wire, i.e. a resistor, heated up by the electricity flowing through it. The wire heats up, in turn heating up the gas.

The Sun is a bit similar to a light bulb. From early spectroscopic studies in the 1800s, we know that it consists of gas, mostly hydrogen and helium. The latter was actually first discovered on Sun giving the element its name from Helios, Greek name for Sun.

Nowadays we also know that this gas is heated up not by directly burning its chemical constituents, but by a special phenomenon that is the reverse of what’s happening in nuclear power plants: nuclear fusion.

While in nuclear power plants uranium splits up and by doing so releases energy (nuclear fission), in nuclear fusion the hydrogen atoms combine to form helium or even more massive particles. In case of light particles like hydrogen this again releases large amounts of energy.

The energy released speeds up the particles in the Sun’s core and in turn these super-heated particles slowly bounce around and raise to Sun’s surface. There, the temperature of the hydrogen-helium gas is 5500 degrees Celsius or near 10 000 degrees Fahrenheit.

A gas this hot will glow literally like the Sun, finally releasing the heated energy to the universe and, consequentially, to us.

Sun continually loses a tiny portion of its mass to keep shining, combining hydrogen to helium in its fusion forge, its core. From observing other stars like it, we know it has enough nuclear fuel to shine for another few billions of years.


Credit : Quora

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Which is the coldest planet?

Pluto is the coldest planet of all, which is not surprising, because it is usually the farthest from the Sun. Inside, it is made up of ice and rock, and the planet has a thick layer of ice over the top.

Is it true? Pluto was named after a cartoon dog.

No. Pluto was the name of the Greek god of the underworld. Also, the first two letters of Pluto, ‘P’ and ‘L’ are the initials of Percival Lowell, who first predicted a planet beyond Neptune.

Who found Pluto’s moon?

An American called Jim Christy discovered Pluto’s moon in 1978. He called it Charon, which was his wife’s name, and also the name of the man who ferried people to the underworld in Ancient Greek mythology.

Is Pluto always farthest from the Sun?

Pluto is so far away from the Sun that it takes 248 years just to orbit it once! But Pluto’s orbit is a funny shape. For 20 years of its orbit, Pluto dips in closer to the Sun than Neptune. When this happens, Neptune is the farthest planet in the Solar System.

Amazing! Pluto is smaller than a country. Pluto is a tiny planet – the smallest in the Solar System. At 2,360 km across, it is smaller than the United States or Russia!

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Which planet has pulling power?

Astronomers knew Neptune must be there before they saw it! They could tell something big was pulling Uranus and they were able to predict exactly where Neptune was – almost 4.5 billion kilometres away from the Sun.

 What’s the weather like on Neptune?

Very, very windy! Winds rip across the planet all the time, much faster than any winds on Earth. There are also lots of storms on Neptune, which show up as dark spots. This means Neptune’s appearance is constantly changing.

Is it true? Triton is Neptune’s only moon.

No. Neptune has seven other moons, but Triton and Nereid are the main ones. Triton is the biggest. It is 2,706 km across – about four-fifths the size of our Moon.

Where would you find pink snow?

When the gas nitrogen freezes, it looks like pink snow! There is frozen nitrogen at Neptune’s north and south poles, and at the poles of its largest moon, Triton. So far from the Sun, Neptune and its moons are bitterly cold places.

Amazing! Triton is one of the coldest places ever recorded! The temperature on the ice-covered moon is minus 236°C. That’s just 37°C away from being the lowest possible temperature in the entire Universe!

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Which planet was found by accident?

Uranus was discovered in 1781. The man, who found it, William Herschel, was not expecting to find a planet at all. He thought he was pointing his homemade telescope at a distant star.

How many moons does Uranus have?

Uranus has at least 17 moons – but there could be more to discover. They are all named after characters from English literature. The main ones are Oberon, Titania, Umbriel, Ariel

and Miranda. Ophelia and Cordelia are the closest.

Amazing! The poles on Uranus are warmer than the equator. Because Uranus is tilted on its side, the poles are the warmest places on the planet. Summer at the South Pole lasts 42 years!

Why is Uranus blue?

The bluish-green is the colour of methane, a stinky gas that makes up part of Uranus’s atmosphere. The other gases in the air there are hydrogen and helium – the gas we use to fill party balloons.

Is it true? Uranus was nearly called George.

Yes. When Herschel discovered the new planet, he wanted to name it after the English king at the time, George III. In the end, it was called Uranus, after the Greek god of the sky.

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Which is the red planet?

Mars was named after the Roman god of war, because of its blood-red colour. The planet looks rusty red because its surface is covered with iron-rich soil and rock. There are no seas on Mars, and it is very cold.

Do Mars have ice at its poles?

Yes. Its south pole is mostly ‘dry ice’, which is frozen carbon dioxide gas. At the North Pole there may be frozen water, mixed with the frozen carbon dioxide. There may be frozen water underground on Mars, too.

Is it true? There is life on Mars.

No. Or at least, there’s no sure sign of any. But long ago, Mars had flowing rivers of water, so there could have been life once, and there may be fossils buried underground.

What are Mars’s   moons like?

Mars’s two tiny moons, Deimos and Phobos, are not round like our Moon. They look more like baked potatoes! They might have been asteroids (space rocks) that Mars captured with its gravity.

Amazing! There’s a record-breaking volcano on Mars. Olympus Mons is about 600 km across and towers over 25 km high. It’s the Solar System’s biggest volcano. Long ago it spurted out runny rivers of black lava.

Picture Credit : Google

Why does the Moon change shape?

It doesn’t really – it’s ball-shaped just like the Earth, but as the Moon travels around the Earth, you see different amounts of its sunlit half. It seems to change gradually from a crescent to a disc, and back again.

Why does the Moon have so many craters?

Because it has been pelted by so many space rocks and has no atmosphere to protect it. One of the biggest craters, called BailIy, is nearly 300 km across. You can make out some of the craters using a good pair of binoculars.

Amazing! You can jump higher on the Moon. The Moon’s gravity is much weaker than Earth’s. This means you would only weigh about a sixth of your Earth-weight there – and you’d be able to jump six times higher!

What is the dark side of the Moon?

It’s the part of the Moon that we can never see from Earth. The Moon takes the same time to orbit the Earth as it does to spin once. This means the same side of the Moon always faces away from the Earth.

Is it true? There are seas on the Moon.

Yes and no. There are dark, rocky plains and craters called maria (Latin for ‘seas’), but they don’t contain water. The first astronauts to visit the Moon landed on the Sea of Tranquility.

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What’s special about our planet?

As far as we know, Earth is the only planet in the Solar System that has life. As well as warmth from the Sun, the other main ingredient for life is liquid water. Earth has plenty of water – in total, it covers about three-quarters of the planet’s surface!

Is it true? There was life on Earth from the start.

No. When Earth first formed it was extremely hot and there was no oxygen. Over millions of years, the planet cooled, oceans formed and oxygen was made. The first life on Earth appeared about 3 billion years ago.

What does Earth look like from space?

It looks beautiful – blue with swirling white clouds. Astronauts in space spend most of their free time gazing at it. They can even make out cities, when they are lit up at night with twinkling lights.

Amazing! The Earth is magnetic. At the centre of the Earth is a core of a molten metal called iron, which makes our planet like a giant magnet. This is what pulls the needle on a compass towards the magnetic North Pole.

Why does our sky go dark at night?

Like all planets, the Earth is spinning as it orbits the Sun. When your part of the planet is facing away from the Sun, its light is blocked out. At the same time, it is daytime for people on the opposite side of the Earth.

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When is a star not a star?

When it’s a planet! Venus is sometimes called the ‘evening star’ because it’s so bright it’s one of the first points of light we see shining as it gets dark. Planets don’t make their own light – they reflect the Sun’s light.

Is it true? Venus is bigger than the Earth.

No. Venus is a fraction smaller than the Earth, but not by much. Venus is about 12,104 km across, whereas Earth is about 650 km wider. Venus’s mass is about four-fifths of Earth’s.

How can a day be longer than a year?

A day is the amount of time a planet takes to spin on its axis, and a year is the time it takes to travel around the Sun. Venus spins on its axis very slowly, but orbits the Sun more quickly than Earth. A day on Venus lasts 243 Earth-days, but a year is only 225 Earth-days.

Amazing! Venus is named after a goddess. Venus was the name of the Roman goddess of love and beauty – just right for the planet, which many people think is the most beautiful object in the sky.

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