Asteroids and comets both orbit the Sun, and are the remains of objects formed in our Solar System. Sometimes their unusual orbits bring them close to planets and moons.
The difference is in their composition. Asteroids typically comprise rocks and metals, while comets also have ice, dust and organic matter in addition to the rocky material. Asteroids stay stable and solid, but if a comet gets close to the Sun, some of its ice melts off.
That’s what gives comets their characteristic tails’ – fuzzy trails pointing away from the Sun that contain ice and compounds such as ammonia It’s likely that Asteroids would have formed closer to the Sun, while comets formed further away in the Solar System, making them able to retain ice.
Some astronomers theorise that comets could have formed closer to the Sun, before being flung out by gravitational forces from gas giants like Jupiter.
Another difference between comets and asteroids is that the former can have huge, elliptical orbits, while asteroids usually have circular, shorter orbits.
A blue whale have weigh the maximum amount as twenty elephants, however it’s no drawback floating within the ocean. The large ships that ferry product round the world will hold thousands of big containers while not sinking. Things float if they’re less dense than the fabric around them-that is, if an exact volume of the thing weighs but a similar volume of its surroundings.
WHY DO THINGS SINK? Gravity pulls things down, even in water. However water pushes upward against things floating in it. If there’s enough water pressure at a lower place one thing to balance its weight, it floats. Wood is a smaller amount dense than water. The load of a block of wood is a smaller amount than the pressure of the water beneath, therefore it floats. Stone is a lot of dense than water, therefore its weight pulls it down in spite of the pressure of the water beneath.
GOING UP Heavy things will fly if they will produce enough upward force to elevate their weight. Before planes were made-up, individuals took to the skies in balloons. These soar into the sky once hot air is pumped up within the large material dome. A balloon choked with hot air weighs but a similar balloon choked with cold air. It’s less dense than the air around it, therefore it soars into the sky. huge balloons will produce enough force to hold individuals with them.
CRAFTY RAFTS The world’s biggest load ships carry up to 18,000 immense containers, every as huge as a truck. Ships work by spreading their weight over a large space. Most of a ship is simply empty house, therefore it weighs but a similar volume of water. Though it’s implausibly significant, it still floats.