Contest Alert 🚨 📢 | The Science of Space

@chasad75 thankks or organising and hosting such an interesting contest on a topics space science. I feel bad for missing the first episode. How ever I would like to invite three fellow Steemians to participate @mesola @rumaisha @yenny47

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Briefly explain the difference between a comet and an asteroid.

Comet

A comet is a mass of ice, rock, and dust, and often has a tail that is made up with dust and other materials.

Asteroid

An asteroid is made up of metallic or non-metallic rocks, and orbits the sun. They can range in size from a few centimeters wide to almost a thousand kilometers across!

Meteoroid

Meteoroids are usually fragments of asteroids or comets, often smaller than 1 meter wide, that fly through space.

What is the name of the closest star to Earth, other than the Sun, and in which constellation is it located?

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Proxima Centauri, lies in the constellation of Centaurus (the Centaur) which lies just 4.2 light-years from the earth.

A planet has been discovered around this star Proxima b potentially Earth-Like Planet Orbiting the Sun's Closest Neighbour.

Name one of the moons of Jupiter and describe one interesting feature about it.

Jupiter has four major moons Io, Ganymede. Europa, Callisto.

EUROPA, MOON OF JUPITER

1,940 miles 3122 kilometre diameter

Surface Temperatures: minus 260° F (minus 160°C)

Gravity: 0.134 of Earth's

Altmosphere: very thin molecular Oxygen

Under its hard crust of ice Europa is thought to have an ocean of liquid water up to 106 miles (170 kilometers) deep. Tides caused by nearby Jupiter could be warming Europa's ocean and driving an ecosystem of allen life forms.

Europa's surface is exceptionally smooth, with few impact craters.

Europa receives about 5.4 sieverts of radiation per day, a fatal dose. Someone at sea level on Earth 0.0014 sieverts per day.

What is a light-year, and why is it used as a unit of measurement in astronomy?

The distance light travels in one year is a light year. Light passes through space at speed of 186,000 miles (300,000 kilometers) per second and 5.88 trillion miles per year.

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Light-years are used to measure distances to objects outside the Solar System.

Andromeda Galaxy 2.5 million ly ( Light year)
Helix Nebula 650 ly
Hyades star cluster 153 ly
Proxima Centauri 4.24 ly

We see the Andromeda Galaxy as it was 2.5 MILLION YEARS IN THE PAST When the light left the galaxy, our ancestors were developing the first stone tools.

Through out the universe light travels in same speed. It's fact that nothing could travel faster than light in space. It moves so fast it can encircle Earth 7.5 times in one second. It could reach moon in 1.3 seconds. So a light year is a distance, a beam of light can reach in a year. It is easier to express cellitial distance in light years than any other other unit.

Thank you for making time to read my post.