Now in the Night Sky: Comet Garradd

by Nancy Atkinson on August 5, 2011

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Comet Garradd on Aug. 1. 2011 as seen from Australia. Credit: Peter Lake.

If you haven’t already, it’s time to start looking for Comet Garradd! This comet, with the nomenclature C/2009 P1, is now coming into small telescope/binocular view so here’s your chance to see the brightest comet in the current night sky. You can find it in the late evening sky in the constellation Pegasus. Viewing it now, Garradd is just coming out the “fuzzball” stage, and its tail is just coming into view. Some say it’s much better looking than that other comet, Elenin, that has been needlessly grabbing some headlines. Comet Garradd was discovered two years ago by Gordon Garradd from the Siding Spring Observatory in Australia, and is currently visible through a small telescope at about magnitude nine.

Above is an image of Comet Garradd from Peter Lake (aka Astroswanny) from Australia.

Throughout the next couple of months, Comet Garradd will get higher and brighter and cut through the Summer Triangle north of Altair. By September, it will drop lower in the west but remain visible in the evening sky until year’s end for observers at mid-northern latitudes. Comet Garradd will peak in brightness late next February at around 6th magnitude, so it could be visible with the naked eye if you have really dark skies. Closest approach to Earth happens next March 5, when Garradd will be 117.7 million miles away. At that time, the comet will be seen flying though the Little Dipper.
Other comets are also currently falling towards the Sun and brightening as they get closer include C/2010 X1 (Elenin), expected to peak near magnitude six in early September, 45P/Honda-Mrkos-Pajdusakova expected to peak brighten past magnitude eight in mid-August, and C/2011 L4 (PANSTARRS) which may become visible to the unaided eye during the early months of 2013.

For more information see the following websites:

Gary Kronk’s Cometology

AstroBob

Aartscope Blog

About 

Nancy Atkinson is Universe Today's Senior Editor. She also works with Astronomy Cast, and is a NASA/JPL Solar System Ambassador.

Anonymous August 5, 2011 at 8:33 PM

Ok I reserved time to get snapshots for this one. Now waiting for a clear sky.

Chris Fields August 5, 2011 at 10:52 PM

Pretty cool…If major earthquakes kep happening every time it was aligned with earth as is the case with Elenin…..I’m sure it’d get a lot more attention as well.

WaxyMary August 6, 2011 at 1:48 AM

Pretty cool…If major earthquakes kep happening every time it was aligned with earth as is the case with Elenin…..I’m sure it’d get a lot more attention as well.

Please Chris, stick to your gossip sites and your comments re those antics. You know nothing of science and should not attempt definitive science posting like the one above.

Mary

Anonymous August 6, 2011 at 11:21 AM

I think you misread his message. He used sarcasm.

The Math Skeptic August 6, 2011 at 4:14 AM

You need to get you pseudoscience straight. Comet Garradd is not capable of causing earthquakes – it doesn’t have nearly enough quantum flux to generate tectonic plate movement.

C/2009 P1 is the celestial body responsible for lost car keys, so expect to spend extra time checking your pockets this month. While we’re at it, you should also know that 45P/Honda-Mrkos-Pajdusakova causes coffee breath, and C/2011 L4 (PANSTARRS) is singularly responsible for dropped mobile phone calls, so you can expect increases ih halitosis and redialing over the next few months and years.

But they’re not caused by C/2010 X1 (Elenin). Not even a little bit.

MatchedRate.com August 7, 2011 at 6:16 PM

Agreed Chris!

WaxyMary August 7, 2011 at 8:08 PM

Olaf2 says: He used sarcasm.

So, is this agreement is to the literal or to the sarcasm?

Mary

Anonymous August 6, 2011 at 11:32 AM

Just a physics question to the experts. (checking if my maths are correct)

What would be the maximum charge an object in space can hold?

I knew it was near zero but I am surprised that for a comet the result would be the equivalent of 6 electrons!
More than 6 electrons and the other electrons would be repelled by these 6 electrons because the gravitational forces can not hold the electrons on the object. They get accelerated into space, and the object is losing any possible charge fast. and I mean fast as in a couple of days or maybe even hours.

It is basically Coulomb force = Gravitational force to keep it on the object.

Torbjörn Larsson August 6, 2011 at 12:34 PM

If you continue that analysis you will find that most likely large objects would try to be positively charged, so you would have to figure out the balance with electrons neutralizing them.

The thing that would keep a body steady state charged would be induction from a magnetic field. Earth can keep a humongous ~ 40 C from rotation (according to an astrophysicist I know), which is a charge corresponding to ~ 1020 electrons. Now that is “astronomical”!

Anonymous August 6, 2011 at 1:46 PM

Positively charged because + charges are heavier and have a stronger gravitational influence than the lighter electrons I think.

Just calculated and I notice 11921 protons charges compared to 6 electron charges max for a comet object. (steady state)

For Earth I calculated 1.57386*10^12 electrons charges max or 2.83294*10^15 proton charges max. (steady state)

I am wondering how you get the 10*10^20 electrons. Because it is rotating?

It really amazed me that it is so low!

Torbjörn Larsson August 7, 2011 at 5:27 PM

In ordinary theory it is enough to have the mass difference (electrons being lighter escapes easier) for the inertia.

Here I would assume the extra weight [sic!] given by gravity (and chemical bounds et cetera) would indeed come into play.

Yes, induction from rotation alone. IIRC the solar contribution (magnetic coupling) is negligible.

Anonymous August 7, 2011 at 8:11 PM

Chemical bonds can indeed also lock some charges, but I doubt that on a comet you will find these chemicals and I also doubt that these chemicals would reside long on a small body because they do not cancel the repelling out.

I am still surprised that the amount of possible stored additional charge on even Earth is that low.

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