Do You Know Why are the Asteroids like Small Planets?

CREDIT: oday.ucf.edu

Asteroids are smaller than any of the planets and measuring up to 900 km (560 miles) across. Asteroids are small rocky or icy bodies that orbit the Sun.  Smaller rocks are called meteors. They are sometimes called minor planets. Most asteroids are found in an orbit between Mars and Jupiter, and more than 7,000 of them have been identified.

The term asteroid is usually applied to objects that are larger than 1.6 kilometers in diameter. One asteroid, called Ida, has a tiny moon all of its own. This is the smallest known satellite in the Solar System. Asteroids were probably formed at the same time as the planets.

Fact File:

CREDIT: cosmostv.org

Many asteroids have struck the Earth already, and many scientists believe that such an impact resulted in the extinction of the dinosaurs about 65 million years ago.

Do You Know Why does it Floods?

If it rains hard and long enough, low lying areas are at risk of flooding. It is a natural occurrence caused by heavy rain.  Flooding is caused by too much rain in too little time.  Human activity influences the frequency and severity of floods, but they are created by Mother Nature.

According to Frank Richards, a National Weather Service hydrologist (a water scientist), "There's more water flowing through the hydrological system than the system can draw off, A flood is an imbalance."

There are two basic  types of floods, Regular River Flood- water slowly climbs over the edges of the river. Flash Flood- when a wall of water quickly sweeps over an area.

Extra water has to go somewhere. Our creeks have a limit of how much water it can hold. When too much rain fall in  just a little time, creeks naturally overflow onto the floodplain. Floodplains are the areas along streams or rivers that are likely to experience repeated flooding. Over thousands of years, nature shaped the floodplain to hold excess water that spills over the banks. Floodplains are designed by nature to flood.

Homes and buildings were often built in floodplains because water was easily available for drinking or commercial uses, floodplain land is often flat and easier to develop than hilly land. It is important to regulate development in higher-risk areas.

Credit: Flood Factors Diagram

A number of factors can contribute to flooding:

• Heavy, intense rainfall

• over-saturated soil, when the ground can't hold any more water.

• High river, stream or reservoir levels caused by the unusually large amounts of rain

• Urbanization, or lots of buildings and parking lots

• Ice jams in rivers

• Frozen soil

• Run-off from a deep snow cover

References:

The Hows and Whys of Floods

Why does it Flood?

Why do Meteors sometimes crash into the Earth?

Credit: astro.lu.se

It is called a meteor  or a shooting star if a lump of  rock or metal burns up before it reaches the ground. It is a meteorite if a large meteor that does not burn up as it plunges through the Earth's atmosphere. As it hits the ground, it travels so fast and shatters into pieces. It causes huge shock waves as it lands. The impact crater in the picture above is to be found at Wolf Creek, Australia, and was caused by a huge meteorite or small asteroid. The amount of energy released would be equivalent to hundreds of nuclear weapons.

Credit:ircamera.as.arizona.edu

The asteroid belt lies between the orbits of Mars and Jupiter. It is thought that this maybe the shattered remains of a planet that has been destroyed by Jupiter's enormous gravity.