Astronomy
Maximum number of meteors can be seen on the nights of December 13-16 and hence it is nicely timed for this weekend.
  • Saturday, December 15, 2018 - 19:45
Flickr /slworking 2

If you have some spare time this weekend, just look up into the firmament! Geminid meteors are going to light up the night sky, and it’s free cosmic fireworks for one and all!

The Geminid meteor shower is one the most active and spectacular annual meteor showers on Earth. Maximum number of meteors can be seen on the nights of December 13-16 and hence it is nicely timed for this weekend. On a dark night, you can catch about 60-100 meteors per hour, if you are lucky!

“Geminids are one of the most brilliant and strong meteor showers we can observe from Earth,” says Dr Peter Jenniskens, the author of meteor science treatise ‘Meteor Showers and Parent Bodies’ and top meteor scientist based at SETI, USA.

All you need is to find a dark patch of sky (relatively free from clouds) and a rural area with less light pollution. You do NOT need any special equipment like telescope or binoculars to enjoy meteor showers.

The meteor shower appears to radiate from constellation Gemini and hence it is named Geminids. In reality, Geminids are dust particles originating from asteroid 3200 Phaethon. When Earth runs through the stream of these dust particles, they burn up in the atmosphere (about 100 km above us) due to friction and create spectacular displays of shooting stars!

“Usually most active meteor showers originate from icy comets. But Geminds is unique in that respect! It originates from a rocky asteroid named 3200 Phaethon,” clarifies Prof Mark Bailey MBE, an accomplished comet expert and past Vice President of the Royal Astronomical Society, London. This asteroid Phaethon is about 6km in diameter and revolves around the sun with an orbital period of about 1.5 years.

“Geminids is a very exciting meteor shower with different orbital resonances with Jupiter. Moreover we find that even Einstein’s general relativistic effects can have a role in their long term orbital evolution in the solar system,” says Dr Galina Ryabova, a seasoned expert on Geminids meteor stream physics, based at Tomsk State University in Siberia, Russia. Dr Ryabova has worked on the dynamics of Geminids meteor stream for decades and has correlated various theoretical predictions and meteor observations over the years.

During the revolution, it comes close to the sun (called perihelion) by as much as one-third the distance between Mercury and the sun. This leads to intense heat on the surface of the asteroid and leftover ices in it sublimate and release dust particles to orbits similar to asteroid’s own orbit. These dust particles collide with Earth at speeds of about 70km per second and fire up, producing Geminid meteors in the sky.

Essentially, these are like high-speed sand grains colliding and lighting up the atmosphere due to strong friction! Most of these particles burn up fully and do not reach the ground as solid! Hence, it is unlikely that we can find any frequent meteorites from this event.

The Northern hemisphere is more favourable to watch this meteor shower and hence India is suited in terms of geography to observe this cosmic event. Meteors can be seen in all parts of the sky and hence you need not worry too much about the direction, orientation or altitude.

The only thing to remember is to stay as far away as possible from bright city lights and pick up a safe spot with less tall trees blocking the view and hope for cloud-free patches in the sky.

(Dr Aswin Sekhar is an Indian astrophysicist and science writer working in UK)