PDA

View Full Version : Comets, when do they usually come?



alleonna
2006-Jul-14, 06:15 PM
Can anybody give me an insight on this? Since I was a child, everytime a comet would come my entire neighborhood would really woke-up and watch it. They are really so happy to see one, same with me. It seems seeing a comet is something to treasure. Does comet have their schedule when to passby our planet? Do they also come on day time?And how come some comets have tails while others don't have?

Sorry, if I have so many questions about comets... just want to really know more. And by the way, I live in the Philippines, anybody knows when are the comets passing my country?

Thanks

ToSeek
2006-Jul-14, 06:25 PM
Comets don't have a schedule, at least not collectively. We had two magnificent ones back in 1997, but nothing comparable since then. Ones like Halley do return periodically, but generally with such long periods that they might as well not be scheduled.

Comets are there in the daytime, they're just harder to see (just like the stars). But there have been comets so bright that they were visible during the day.

Almost all comets near the Sun have tails as the Sun heats them up and the material evaporates off them and is blown away.

I don't know of any significant comets (ones you can see without a telescope) coming up any time soon.

antoniseb
2006-Jul-14, 06:27 PM
Hi Alleonna welcome to the BAUT forum.

Comets don't come on a schedule. We normally get a comet bright enough to see without help once every few years.

cjl
2006-Jul-14, 06:32 PM
All comets have tails when they are near the sun. They are caused by the ice and dust getting sublimated from the suns heat and the resulting gas causes the tail.

Yes, some comets have schedules. They are in certain orbits, which approach the sun at specific times. Others have not been discovered yet. Some are disturbed when they pass by large bodies and their schedule (and orbit) change. Most of the ones you hear about are fairly well known and periodic ones. However, just because they have a schedule for approaching the sun does not mean that they will necessarily be spectacular and bright each time. There is no real schedule for bright and spectacular comets.

As for coming at daytime? They are usually visible for many days when they approach the earth, and if the sky and sun didn't wash them out, yes they would be visible at daytime too.

Here (http://www.nineplanets.org/comets.html) is some good info on comets, and there is some more info here (http://en.wikipedia.org/wiki/Comet).

As for your last question?
Comets don't pass one country more than any other. A comet that approaches the earth close enough to see is visible from most places on earth (with a couple minor exceptions) at the local nighttime. I can't say when the next bright one will be visible, but there are currently many many comets visible with the right equipment. Most would be rather disappointing however, averaging many hundreds of times dimmer than visible with the naked eye.

If you have any more questions, feel free to ask, and welcome to BAUT :)

tony873004
2006-Jul-14, 09:14 PM
Some comets are better positioned for Northern hemisphere or for Southern Hemisphere. Being close to the equator, you should have a good view of both collections.

Hale-Bopp, the bright one in 1997 was discovered a few years before it became a naked-eye object. There are none that we know of in the next few years.

However, comet Hyakutake was discovered only 2 months before its peaked at naked-eye visibility. So keep your fingers crossed. There's a small chance that in September you'll be staring at a very impressive as-of-yet undiscovered comet.

Gillianren
2006-Jul-14, 10:24 PM
I think perhaps what is being asked about is not comets by meteor showers, which do have schedules, though individual ones may appear at any time.