Tag: science & technology

When comets approach the Sun, solar radiation causes their frozen ices to sublimate (change directly from solid to gas). This creates a glowing coma and two tails - a dust tail and an ion tail - that always point away from the Sun. The 'fire' distractor is wrong because space lacks oxygen for combustion.

A meteorite is specifically defined as a solid piece of debris from an asteroid, comet, or meteoroid that survives its passage through Earth's atmosphere and reaches the ground. The distinction is that meteors are the atmospheric light phenomena, while meteorites are the actual rocks that land. Option C describes a satellite, not a meteorite.

Comets are astronomical objects composed of ice, dust, and rocky material that orbit the Sun. When they approach the Sun, they develop spectacular tails of gas and dust that can extend millions of kilometers. The tail always points away from the Sun due to solar wind and radiation pressure.

The farthest human-made object, Voyager 1, is about 159 astronomical units from Earth (about 15.8 billion miles or 24 billion km). Since 1 light-year equals about 63,241 AU, this is less than 0.003 light-years - far less than one light-day (which is about 173 AU). The spacecraft have barely left our Sun's immediate neighborhood.

The most distant observed galaxy, GN-z11, has its light reaching us after about 13.4 billion years. However, due to the expansion of the universe during that time, the galaxy is now about 32 billion light-years away (comoving distance). The 20 billion figure in option B is a reasonable approximation accounting for cosmic expansion since the light was emitted.

The Sun orbits the center of the Milky Way galaxy at approximately 220-230 kilometers per second. Converting to miles gives about 150 miles per second. This orbital period takes about 225-250 million years to complete one revolution around the galactic center.

The Sun orbits the center of the Milky Way galaxy at approximately 220-230 kilometers per second. Converting to miles gives about 150 miles per second. This orbital period takes about 225-250 million years to complete one revolution around the galactic center. This is a duplicate of question 110069.

The Moon's surface gravity is about 1/6th of Earth's gravity. Therefore, a person weighing 60 kg on Earth would weigh only about 10 kg on the Moon. This is why astronauts could jump much higher on the lunar surface. The Moon still has gravity (it's what keeps astronauts from floating away), it's just weaker.

Light travels at approximately 299,792 km/s. The average Earth-Sun distance is about 150 million km. Dividing gives about 500 seconds, or roughly 8 minutes and 20 seconds. This means we always see the Sun as it was 8 minutes ago - if it suddenly disappeared, we wouldn't know for 8 minutes.