June 30 is World Meteor Watch Day.
Meteors are also known as ‘shooting stars’. Look up into the night sky and you might see a sudden streak of light. For a fraction of a second, it lights a trail, leaving you in awe at the wonders of nature. The light glows from a heated and glowing meteoroid falling through the Earth’s atmosphere.
Make a wish
Have you heard people say, “Wish upon a shooting star and it will come true”?
This is believed to have originated in Greece around AD 127-151, when Greek astronomer Ptolemy wrote that sometimes the Gods out of curiosity, peered down at the Earth from between the spheres. Some stars would slip out through the gap, becoming visible to us as shooting stars. It was thought that as the Gods were looking at us, they would be more receptive to the wishes we make!
Its very name has a Greek origin. Meteor is derived from meteôros which means “high in the air”.
However, today, we know that shooting stars are small, varying from the size of a closed fist to the size of a pebble. Thousands of meteoroids enter the earth’s atmosphere every day. But, only a few of them reach the surface, and that’s when we see them.
Meteor Watch Day, is actually a celebration night. It’s time to switch off your televisions and computers and step outside to gaze at the night sky.
What is it?
A meteoroid is a small rocky or metallic body that is travelling through outer space. They are much smaller than an asteroid. When a meteoroid enters the Earth’s atmosphere at a speed higher than 20 km/s (72,000 km/h; 45,000 mph) aerodynamic heating of that object produces a streak of light, from the glowing object as well as the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor or “shooting star”. When a series of meteors appear seemingly appearing from the same spot in the sky, it is called a meteor shower.
Journey to discovery
It is only in the early 19 century that meteors have been recognised as an astronomical phenomenon. Earlier to this, it was thought to be an atmospheric phenomenon similar to lightning. In 1807, a chemistry professor in Yale University, Connecticut, U.S., investigated a meteorite that fell in Connecticut and came to the conclusion that it came from space. But no one thought much of what he said. Then, in November 1833, there was a spectacular meteor shower and people across the eastern U.S. saw it.
Astronomer Denison Olmsted made an extensive study of this storm, and concluded that it did indeed have a cosmic origin. After reviewing historical records, Heinrich Wilhelm Matthias Olbers predicted that the storm would return in 1867. This prediction attracted the attention of other astronomers.
Hubert A. Newton, an American mathematician and astronomer contributed to Olmsted’s theory that meteors were a part of a mass of bodies moving round the sun in a fixed orbit.
Giovanni Schiaparelli, an Italian astronomer and science historian, connected the meteor showers (leonids) with the comet Tempel-Tuttle. This confirmed that meteors had a cosmic origin.
Quick facts
Meteors are popularly known as shooting stars or falling stars. They are objects that fall through the earth’s atmosphere and glow brightly as the thick air resists their passage. These objects can be as small as a dust particle or as large as a rock.
A meteor is different from a meteorite, which is actually a meteor that manages to survive its journey through the Earth’s atmosphere and actually hits the ground.
A meteor shower happens when the Earth, in its orbit, crosses the path of a meteor stream, which is a group of meteoroids — a small hunk of rock or metal that travels through space. Meteoroids are smaller than asteroids and are usually the size of a pebble.
June 30 also happens to be Asteroid Day. It was created to raise awareness on the danger of asteroids. The date was chosen for a historic day in 1908 when an asteroid crashed into Tunguska, Siberia, and destroyed 770 square miles of forest.
