Starwatch: a sparkling year for the Geminids I Geminid meteor shower: When can I see the spectacular display of shooting stars? I All about the Geminid meteor shower that is set to light up the sky on December 13

The number of meteors can reach up to 120 per hour.   | Photo Credit: REUTERS

You can enjoy the meteor shower display after 10 p.m. IST of December 13 till the early hours the next day.

Star-lovers and sky-enthusiasts can enjoy a meteor shower display on December 13 after 10 p.m., and in the early morning hours of December 14, if clouds and light pollution do not play spoilsport. Reach a spot without city lights, maybe the suburbs, and you can enjoy the Geminid meteor shower.

Here, Dr. Debiprosad Duari, Director, M. P. Birla Planetarium, Kolkata explains meteors and the Geminid meteor shower.

What are meteors and meteoroids?

Rocks and dust particles from space that are about to collide with Earth's atmosphere are called meteoroids. Those that enter and streak through the atmosphere are called meteors.

What causes a meteor shower?

Usually when comets, which are chunks of ice with lot of dust, come close to the sun, the ice melts and the dust and rocks are left behind along the orbit of the comet. If Earth, in its yearly motion around the Sun happens to pass through such a debris trail, they enter the Earth’s atmosphere with considerable speed and due to friction in the atmosphere, burns up and give rise to not only a single bright streak in the sky but numerous meteors, called meteor shower.

Why is the Geminid meteor shower called so?

Geminid meteor shower is so named because the meteors appear to originate from the constellation of Gemini in the night sky. It is not a comet but an unusual asteroid called 3200 Phaethon, discovered in 1983, that is the origin of the meteors.

So this shower is from an asteroid. Now what exactly is an asteroid?

Asteroids are rocky bodies going round the Sun, originating from a region between the orbit of Mars and Jupiter. Unlike the planets, their orbits are sometimes extremely elliptical and intersect the orbit of Mars and even Earth. The Earth-orbit-crossing asteroids are called Apollo Asteroids.

Can you tell us more about the asteroid 3200 Phaethon that is causing this shower?

3200 Phaethon, named after the son of the Sun god Helios, is an Apollo Asteroid that may have undergone a collision with another object in the distant past to produce the stream of particles that Earth runs into — creating this meteor shower.

3200 Phaethon, a 5.1-k.m.-long piece of rock, has characteristics which are close to a comet. In its close approach to Sun, it sheds huge amount of rock and dust in its path and Earth happens to pass that path every year during December 4-16.

So we can watch the Geminid meteor shower every year?

Yes. Generally the meteor shower associated with 3200 Phaethon peaks around second week of December every year and are quite numerous.

So I can watch the shower whole night?

The shower will start at around 10:00 p.m., when the Gemini constellation will be visible in the northeastern sky, a little above and right of the familiar Orion constellation. The shower is predicted to be at its maximum around 2:00 a.m. on Dec. 14 early morning when the Gemini constellation will be almost overhead and the number of meteors can reach up to 120 per hour. This year the expectations to observe this shower is high since there will only be a crescent moon and the moonlight will not be bright to suppress this celestial firework show. In India, the moon will rise around 01:40 a.m., the timing varying slightly, depending upon the geographical location.

Do I need binoculars to see the meteors?

Since the meteors are relatively slow moving, the bright streaks of light will be easily visible. You do not need a binocular or telescope for enjoying the show.

Interested people are urged to go out of the city light limits and just lie down on the ground with enough warm clothing and keep an eye on the sky. Though the meteors tend to originate from the Gemini constellation, they can be observed at most parts of the sky.

The reliable Geminids meteor shower has returned to our sky and, with the Moon as an unobtrusive waning crescent before dawn, we are in for a spectacular display of meteors over the coming week.

Active between the 8th and 17th, the shower is expected to peak overnight on the 13th-14th, bringing more than 100 meteors an hour for an observer under perfect skies. Since high rates persist for more than a day, there should be an excellent show on the previous night, but probably less so on the next one.

Starwatch: meteors and their icy origins in the heart of a comet

 

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The radiant point, from which the meteor paths appear to diverge, lies close to Gemini’s star Castor, which climbs from low in the NE at nightfall to pass high on the meridian at 02:00. Our chart spans some 100° from Leo to Taurus and is centred on Gemini, which stands to the NE of the unmistakable form of Orion. Of course, the meteors appear in every part of the sky – it is just their paths that point back to the radiant.

Travelling at 35km per second, Geminid meteoroids trace long sparkling paths as they disintegrate in the upper atmosphere. However, unlike some meteors, they rarely leave persistent glowing trains in their wake. The meteoroids are thought to derive from the 5km-diameter asteroid Phaethon, which is roasted every 523 days as it sweeps within 21 million kilometres of the Sun at perihelion – closer than any other named asteroid. Its rocks are thought to fracture in the heat, allowing splinters and dust to escape its tiny gravitational pull and spread out around its orbit.

Phaethon passes about 10 million kilometres from the Earth on the 16th in its closest approach since its discovery in 1983, though whether this will result in even more Geminids than usual is questionable. It should be a telescopic object of around the tenth magnitude as it speeds south-westwards from the vicinity of Capella in Auriga on the 11th, through Perseus and Andromeda to the Square of Pegasus.

Also plotted on our chart are Praesepe, the Beehive, in Cancer, and M35, at the feet of Gemini, which are both open star clusters just naked-eye-visible but easy through binoculars. Hydra the Water Snake, the largest constellation, stretches more than 100° around the sky from its head to the S of Cancer to the tip of its tail, which lies S of the conspicuous planet Jupiter in our SE predawn sky. The Moon stands above Jupiter and to the left of Mars on the morning of the 14th.

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