Category The Universe, Exploring the Universe, Solar System, The Moon, Space, Space Travel

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.

Picture Credit : Google

What is the Solar System?

Solar means ‘of the Sun’. The Solar System is centered on the Sun, the shining ball in the sky. It includes the family of nine planets orbiting (travelling around) the Sun, as well as the moons of these planets, and smaller objects, such as comets, asteroids, and bits of space rock. The powerful pull of an invisible force called gravity from the Sun stops these bodies from flying off into deepest space.

Is it true? All planets have one moon.

No. Our planet Earth has one moon, called the Moon. But many of the planets have more than one. Our neighbour Mars, for instance, has two! Only the two planets closest to the Sun – Mercury and Venus – have no moons at all.

Amazing! Saturn’s not the only planet with rings. Saturn’s rings are the easiest to see, but Jupiter, Neptune and Uranus have them, too. Saturn has seven main rings, and then hundreds of thinner rings, called ringlets.

Picture Credit : Google

How hot is the Sun?

In deserts here on Earth, heat that has travelled 150 million km from the Sun can be hot enough to fry an egg. The Sun’s surface is a super-hot 6,000°C, and its centre or core is even hotter.

Amazing! The Sun is a star – a gigantic ball of burning gas. It has been shining for about five billion years.

Why must you never look at the Sun?

Not even sunglasses fully protect your eyes from the Sun’s dangerous ultraviolet (UV) rays. UV can burn your eyes and make you blind. If you want to see the Sun safely, ask an adult to show you how to project its image on to a sheet of paper.

Is it true? The Sun has spots.

Yes. The Sun is not the same colour all over. Some areas of its surface are darker. These spots are little pockets that are slightly cooler. Of course, sunspots are only ‘little’ compared to the Sun – some grow to be as large as Jupiter, the biggest planet in the Solar System!

When does the Sun go out?

When there’s a total eclipse. This happens when the Moon’s path takes it between the Earth and the Sun, and the Moon casts a shadow across the surface of the Earth.

Picture Credit : Google

What does Mercury look like?

Planet Mercury looks very like our Moon. It’s about the same size and it’s covered in craters, where bits of space rock have crash-landed on its surface. The biggest crater is the Caloris Basin, which is about 1,300 km across. Mercury also has huge plains, rolling hills, deep gorges, chasms, and cliffs.

Is it true? Mercury is the smallest planet.

No. Mercury is only about a third the size of the Earth, but Pluto is even smaller. If you could put them on the scales, it would take 21 Plutos to balance one Mercury.

Is Mercury the hottest planet?

Mercury is the planet closest to the Sun, but its neighbour Venus is even hotter, because it has clouds to keep in the heat.

What is the weather like on Mercury?

Mercury doesn’t have any weather, because it has no air and hardly any atmosphere. That means there are no clouds to shield the surface of the planet from the baking-hot Sun during the day, or to keep in the heat at night. There is no wind or rain on Mercury, either.

Amazing! Mercury is the fastest planet. Mercury zooms around the sun in just 88 days, at an incredible 173,000 kph. That makes it faster than any space rocket ever incented.

Picture Credit : Google

How long does light from the Sun take to reach Earth?

The short answer is that it takes sunlight an average of 8 minutes and 20 seconds to travel from the Sun to the Earth.

If the Sun suddenly disappeared from the Universe (not that this could actually happen, don’t panic), it would take a little more than 8 minutes before you realized it was time to put on a sweater.

Here’s the math. We orbit the Sun at a distance of about 150 million km. Light moves at 300,000 kilometers/second. Divide these and you get 500 seconds, or 8 minutes and 20 seconds.

You probably know that photons are created by fusion reactions inside the Sun’s core. They start off as gamma radiation and then are emitted and absorbed countless times in the Sun’s radiative zone, wandering around inside the massive star before they finally reach the surface.

What you probably don’t know, is that these photons striking your eyeballs were ACTUALLY created tens of thousands of years ago and it took that long for them to be emitted by the sun.

Once they escaped the surface, it was only a short 8 minutes for those photons to cross the vast distance from the Sun to the Earth.

 

Picture Credit : Google

What Does a Sunrise-Sunset look like on Mars?

NASA’s Viking 1 lander first showed humans what a sunset looked like on Mars in 1976. Several more Red Planet robots have since sent back a variety of views of Martian sunrises and sunsets.

Some color-corrected, blue-hued images preview what human Mars explorers might one day see while relaxing after a hard day’s work on the fourth planet.

Because Mars is farther from the Sun than Earth, the Sun appears only about two-thirds the size we see when we watch sunsets here on Earth.

Just as colors are made more dramatic in sunsets on Earth, Martian sunsets would appear bluish to human observers watching from the red planet. Fine dust makes the blue near the Sun’s part of the sky much more prominent, while normal daylight makes the Red Planet’s familiar rusty dust color more prominent.

 

Picture Credit : Google