Sun Professor Brian Cox shows you how to view comets in 2013

January 8, 2013 by  
Filed under Solar Energy Tips

THIS year promises to be one of the most exciting in a long time for anyone
who enjoys looking at the stars.

That’s because we will be visited by two travellers from the far, icy reaches
of the outer solar system.

In March, a comet with the catchy name “C/2011 L4 (PanSTARRS)” will be visible
from the UK, and it could be spectacular.

This ball of rock and ice was discovered in the summer of 2011 by the
Pan-STARRS telescope on the Hawaiian island of Maui.

Pan-STARRS was designed specifically for this job — to detect and catalogue
the huge numbers of asteroids and comets that swarm around the sun, along
with the more familiar planets and moons of the solar system.

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This comet probably came from the Oort cloud, a vast swarm of trillions of
rocky snowballs, many larger than a mile across, that extends almost a
quarter of the way out to our nearest neighbouring star system, Alpha
Centauri. It hasn’t passed our way before, which suggests that it was nudged
out of its distant orbit by the gravitational tug of the stars of the Milky
Way only a few million years ago.

C/2011 L4 will make its closest flyby of Earth on March 5, at a distance of
around 90million miles, which is close enough to make it, possibly, the
brightest star in the sky, outshining even the planet Venus.

It is thought that this comet will return — but not for 110,000 years. C/2011
L4 will be a beautiful sight, but it may just be a warm-up for a spectacular
treat in November. Comet C/2012 S1 (ISON) was discovered by two Russian
astronomers in September.

The comet will pass only three quarters of a million miles above the surface
of the Sun on November 28, and, if it stays intact, it will sweep by the
Earth at a distance of 39million miles on Boxing Day 2013.

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With luck, we may get a spectacular display. The comet could outshine the
moon, with a spectacular tail sweeping across the night sky. We will fly
through the tail in mid-January 2014, which could lead to meteor showers.
There are many reasons to be fascinated by comets.

It is now thought that comets delivered a large amount of water to Earth in
the early history of the solar system.

If you have a glass of water, you will almost certainly be drinking at least
some water from an ancient comet.

But comets are also undoubtedly a threat, which is one of the reasons that
telescopes such as PanSTARRS are constantly searching the skies for them.
The extinction of the dinosaurs 65million years ago is now widely thought to
have been the result of an impact from space, and this could have been a

The damage comets can do to planets was dramatically confirmed in 1994 when
Shoemaker-Levy 9 slammed into Jupiter.

Brian Cox

Its impact left a series of scars in the gas giant’s atmosphere big enough to
swallow the Earth!

So while neither of the comets of 2013 pose any threat to us, it is vital that
we keep our eyes peeled.

This is one of the genuinely important justifications for learning to live and
work in space. One day, we will have to move a comet or asteroid out of
harm’s way.

As the great astronomer Carl Sagan memorably said: “If the dinosaurs had built
a space program, they would still be around.”

Meanwhile, to get ready for the spectacular year of treats ahead, below is a
basic guide to how to start looking at the night skies — and some of the
wonders you can see even if no comets happen to be in sight.

How to know your asteroid from your elbow

PLANETS: A planet in our solar system is a body that orbits the sun and
has enough gravitational pull to be nearly spherical and to clear its
neighbourhood of debris.

There are eight planets in our solar system. If a planet orbits a star other
than the sun, it is called an exoplanet.

MOON: The moon is the Earth’s only natural satellite. The other planets
in the solar system, with the exception of Mercury and Venus, also have
moons. Jupiter and Saturn have more than 60 each.

DEEP SKY OBJECTS: Deep sky objects lie outside the solar system,
nestled among the stars.

Nebulae (glowing clouds of gas and dust), star clusters, globular clusters
(ancient and densely packed clusters of stars that exist in a halo around a
galaxy’s core) and galaxies are known as deep sky objects. These are amazing
things to look for.

With a few notable exceptions, all of the objects, except galaxies, are
located within our own Milky Way galaxy. There are many external galaxies to
our own, each a collection of stars, gas and dust bound together by gravity.
Our own Milky Way galaxy contains several hundred billion stars.

METEORS: When small particles, known as meteoroids, collide with the
Earth they pass through our atmosphere and vaporize.

This results in a streak of light known as a meteor or shooting star. The
particles are typically the size of a grain of sand but may occasionally be
larger. Those that make it through the atmosphere intact to land on Earth
are called meteorites.

CONSTELLATIONS: Constellations are patterns of stars in the sky,
historically named after objects, animals and mythological characters.

There are 88 constellations of which roughly two thirds can be seen from the

STARS: Stars are spheres of gas that emit energy, including light,
through nuclear processes.

ASTEROIDS: Small rocky or metallic bodies that orbit the Sun and mainly
lie between the orbits of Mars and Jupiter.

Some do orbit outside of this zone and currently there are several thousand
known to come in close proximity to the Earth.

Brian Cox hosts Stargazing Live, which kicks off tonight on BBC2 at 8pm. To
learn more Stargazing tips visit

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