In order to observe asteroids you will need a telescope and a good star chart.
Since they look exactly like stars, you should be patient and observe them for a few nights in a row.
If the object moves with respect to the stars you probably have found an asteroid.
However, if you have a motorized mount mechanism on your telescope and photograph the sky for few hours,
the stars would be like dots on your pictures, while asteroids would look like short streaks.
Why do we need to study asteroids if they are so small?
They can give valuable information about the material that formed our Solar System and some of them
could strike the Earth, possibly killing life!
, the largest asteroid with a diameter of about 580 miles,
was discovered in 1801 by Giuseppe Piazzi
and named after the Roman goddess of the harvest,
growing plants, and motherly love.
The next year, Heinrich Olbers
named after Pallas Athena,
the Greek goddess of wisdom.
A few years later, Olbers also found another asteroid and named it Vesta
, for the ancient Roman goddess of the hearth.
Asteroid hunting continues today. Asteroids are classified by their brightness, chemical composition and position in the solar system.
Some asteroids look dark, since they reflect only a small percentage of sunlight, while others reflect more and look brighter.
Their brightness is determined mainly by the chemical composition. About 75% of asteroids contain high amounts of carbon
These high carbon asteroids are classified as C-type
asteroids. About 17% of asteroids are formed
material and iron
, which makes them brighter.
These silicate rich asteroids are called S-type
asteroids, containing mostly metals are rare, and probably were formed in the nuclei of other bodies.
Asteroids are divided in several groups according to their location in the solar system.
For example, Trojans
share the same orbit as Jupiter, while Near Earth
objects cross the Earth's Orbit.
When an asteroid, comet fragment, or other small body --commonly called a meteoroid-- enters the Earth's atmosphere,
it produces a spectacular sight called a meteor or shooting star.
Friction with the air molecules heats, melts, and typically burns the meteoroid while it is still high in the atmosphere.
However, if the body is large enough, it can reach the surface.
Astronomers called these chunks meteorites.
Meteorites might be pieces of comets or planets, but the majority of them are parts of asteroids.
Scientists study them determining their chemical composition and structure to learn more about the material that formed our Solar System.
Asteroids were first studied in depth by the Galileo
spacecraft on its way to Jupiter.
This mission revealed that the asteroids Ida
are small bodies with
irregular shapes and heavily cratered surfaces.
spacecraft was a project designated to study the asteroid Eros
which is one of the largest asteroids that comes close to the Earth.
NEAR took thousands of pictures and measured the asteroid's shape precisely using a laser rangefinder.
While the magnetometer did not register any magnetic field, the x-ray and gamma-ray spectrometers were successfully used
to measure chemical composition.
Near Earth Objects (NEOs) are objects (primarily asteroids and comets) whose orbits cross the Earth's.
They are very interesting and challenging at the same time.
Their small sizes make early detection very difficult.
However, if they are close enough and their orbits line up with the Earth they could be very dangerous.
Statistics show that about every 100 years the Earth is hit by a small asteroid.
A significantly large one (about 1 mile in diameter) hits the Earth about once every million years.
However, one 19-mile asteroid probably led to the extinction of the dinosaurs 65 million years ago.
It hit Central America with such force that it caused global climate change resulting in the deaths of the dinosaurs and many other species.
Could this happen again?