Perseids Meteor Shower: Expert answers your questions about shooting stars

Aug 08, 2011

Ever wonder what makes meteor showers splash across the sky? Or what makes them so consistent? Or why they were dubbed "shooting stars"?

Join professional astronomer Scott Fisher as he discusses the latest phenomenon, the Persieds Meteor Shower - an annual summer phenomenon that is expected to producer 20 to 25 meteors (shooting stars) per hour. He will be online Monday, Aug. 8, at 1 p.m. ET, to chat about the meteor shower, when the best time to view the shooting stars are and more.

Have a question? Ask now.

Hi everyone! This is Scott, it looks like I am all setup here in my office, I'm really looking forward to the chat today.

Thanks much for the questions that have already been submitted, it looks like we have a lot of interest in meteors and the upcoming Perseid meteor shower.  Feel free to hop in and ask a question, I will attempt to answer them all. So let's get  to it, shall we?

When is the best date/time for viewing?

Let's go ahead and answer this important question first. The peak of the Perseid Meteor shower for 2011 will be on the night of August 12-13. The best viewing will be from after 10:00 PM until 4:00 AM or so.

Since the moon will be a factor this year, what will be the best year in the near future, as far as viewing conditions go, to watch the Perseids? Also, is it likely we might see some variability (hopefully upwards) in the rates in years to come?

Well, the Moon is not being very kind to our plans for observing the Perseids this year. It will be an almost full Moon on August 12/13 adn it will be so bright it will wash out many of the faint meteors we are trying to see.

We do know that the number of meteors seen varies from year to year, but unfortunately we have no real way to predict if we will see more (higher rates) in the future. We are just going to have to watch each year to see.

 

Do we enter the debris left over by the comet? Does this debris orbit the sun ? or is it just "hanging" there and we go threw it each year?

We do enter the debris left over by the comet and yep, that material does orbit around the Sun just like the Earth does. You can think of the 'comet debris' as a very very thin ring-shaped cloud of material around the Sun, once a year (during early August) the orbit of the Earth carries our planet through this ring, that is why we get these small particles raining down through our atmpsphere and causing meteors. So in some sense that comet debris is just hanging around out there and here comes the Earth flying through it causing the meteor shower.

 

I have never seen a meteor. I have tried looking during period of meteor showers and nothing happens when I look. I have looked in rural areas in clear skies, and nothing. What days and hours would be best to see these 20 to 25 meteors per hour? I just want to see one.

Well, I hope you get to see a meteor soon, they really are a great sight to see! It sounds like you are doing everything correctly, you are in a rural area, have dark skies above, and know to look when a shower is predicted.

For the upcoming Perseids the best time to observe will be after 10 PM on the night of August 12 to the morning of August 13. Be sure you have a wide-open sky, with as few clouds as possible, and also give your eyes time to adjust to the dark! Take a blanket, look straight up and try to take in as much of the sky as possible since meteors can appear anywhere in the sky. Good luck!

With the popular belief that there are might be a infinite number of comets in the universe, what makes the Comet Hale-Bopp so visible to the naked eye while other's not so much? Does this have anything to do with the rotation of the Earth or the fact that it is closer to the Earth at that period in time and other comets are not?

It turns out there are lots of factors that help determine how bright a comet will be, and Hale-Bopp was a great one, wasn't it??

You mentioned one important factor, how close the comet is to the Earth. The distance from Earth to the comet determines how bright the comet will look and how big it will look in the sky. Hale-Bopp was pretty close and had a pretty big tail, that is why it looked so great in the sky. Other comets may be intrinsically bigger or brighter, but if they are very far away from Earth they will not look very impressive.

Other factors are things like how close the comet is to the Sun. This is very important since it is the Sun that is 'melting' the comet and causing its material to fly off into space. The size of the nucleus of the comet helps determine how must gas and dust is available to form the cometary tail, and the size of the dust particules shed by the nucleus also has an effect on the brightness.

Even though the peak night for viewing the meteor shower is Aug 12/13, if we have a clear night for watching between tonight and Friday night - or even the nights within the following week, would we expect to see some meteors? Maybe just not as many as Friday night?

Good point! I want to emphasize the peak of the shower is on the night of August 12. The shower is already underway, just at a lower rate of events. Definitely keep your eyes peeled between now and the peak, the Perseids are known to produce a large number of extra bright meteors and they can occur at any time.

Slightly off topic but: could you recommend a monthly column that tells you what stars/planets are visible? Washington Post sometimes has SkyWatch, but not always. My father was an amateur astronomer, building his own telescope (so heavy he had to build a cement block to hold it), and I remember fondly seeing Jupiter. Thanks.

There are lots of guides and informational web pages out there. Here are two that I use quite a bit:

http://stardate.org/

http://www.astronomy.com/News-Observing/Sky%20this%20Month.aspx

Take a look there!

 

Considering the observatory with which you are most closely associated, once and for all, what's the correct pronounciation of "Gemini"? Thanks for setting us straight!

As you might guess, there are on-going discussions about this, even within Gemini! There are two ways that it is pronounced most of the time. American and some British people tend to pronounce it Gem-in-eye, non-native english speakers (and the rest of the Brits!) tend to say Gem-in-knee. So as far as I can tell, they are both right!

Do you know the They Might Be Giants song "What is a Shooting Star?" Is it scientifically accurate, or just a clever pop song?

Yes! I do know that song, and it is a good one. It is correct, and we scientists thank TMBG for producing cool songs that are scientifically accurate! BTW, I also think it is a clever pop song, and it is at least as cool as "Particle Man".

What is the chances of one of the meteors reaching the earth? What is the largest meteor that has beem viewed - length & wideth?

Well, there is always some chance that a meteor will reach the earth! If one does, it will then be called a meteorite. A quick search tells me that the largest known version is the "Hoba" meteorite, it is roughly 9 feet by 9 feet by 3 feet and weighs about 66 tons!

When would we be most likely to see the greatest concentration of meteors? Are the number of meteors increasing, remaining constant or decreasing annually? David Bilan

Hi David,

This is really tough to predict, but we believe that the peak of the shower will be in the early morning hours of August 12/13. The number of meteors seen in the Perseid shower does vary from year to year but it has stayed roughly constant for the last few years with a rate of ~100 meteors per hour.

 

How often do meteor showers occur? Are there a variety of showers? Do we see any particular ones consistently?

There are many meteor showers throughout the year, and observers do see them consistently. For example, the Perseids peak during the middle of each August. As a different example, later this year (in late October) the Orionid meteor shower will peak.

Is there a particular place in the sky or direction we should be looking?

It turns out that this shower is called the Perseids since the "radiant" (the point in the sky where the meteors seem to originate) for this shower is in the constellation of Perseus. So, in some sense keep a careful eye on that constellation. However! The best thing to do is to take a blanket into an area where you have a wide-open sky above and keep your eyes on as much of the sky as possible since meteors do appear anywhere in the sky.

How visible will the Perseid meteor show be in New England verus the Middle Atlantic states?

I think that this will be mostly determined by how clear of a sky you have. It is impossible to predict where any given meteor will be visible, so you may see a few in Maine that we won't see in DC (and we may see a few that you can't), but the driving factor will be if you have clouds or not. So please drive out of town to find some clear skies!

I live in the Silver Spring area of MD. Does anyone know a good, convenient, location for viewing with out driving several hours?

The biggest consideration is to be away from city lights and the orange glow of them. I don't know of any specific spots near Silver Spring, but what you are looking for is a place where you can see a large fraction of the sky (so avoid tree-lined roads please!) with few if any lights in the area. If you are in a place where you can see all of the stars of the Big Dipper, you are doing OK!

It has probably been about 8-10 years since I have been out during one of the known meteor showers. OK, I am too lazy to go out to someplace far away from the suburban lights in the middle of the night. Assuming the sky is clear of clouds, how will it be watching from a dark backyard?

If you have a sky that is clear from clouds, you are already more than halfway there. Keep in mind that many of the meteors will be roughly as bright as an average star, so not super bright. If you can still see much of the city skyglow, the backyard will not be optimal for observing. You will surely be able to see the brightest of the meteors, but the fainter ones may be washed out by the light pollution.

Since the full moon might make this shower hard to see, what is the next best meteor shower that we might get to view?

There are two more showers later this year where the Moon is better positioned in the sky. For the Orionids on October 21 and the Leonids on November 17 the Moon does not rise until well after modnight. So, for the first half of each of those nights the observing conditions should be favorable.

Any particular area of the sky to look on Friday night around 10-11p? This is my first time dragging my 5-year-old out of bed for a meteor shower so I have to be able to find them.... We tried viewing the eclipse last winter and it was too cold for her when I woke her up about 2am.

Yes! I always like to hear of young astronomers getting out there to observe, even if that involves being woken up by astronomically minded parents!

The best place to look will be toward the constellation Peresus since that is where the shower originates. Perseus will be low in the northeastern sky around 10 PM on the 12th, take a peek at this sky map if you need help:

http://www.skymaps.com/skymaps/tesmn1108.pdf

But, please keep an eye on as much of the sky as possible since meteors can (and do) appear anywhere in the sky.

 

 

Will it be worth waking up in the middle of the night to see it, given I live in the DC suburbs? I'm concerned about all the light pollution. Thanks.

This is a tough one. First, it is always worth it to get up to see something cool like this. Having said that... this will be a pretty tough situation since the Moon will be close to full and there is that light pollution to deal with. The bottom line is that you will definitely be able to see brighter meteors, but the fainter ones will be overwhelmed by the Moon and city lights. Even though I have seen them many times before, I will be up and watching!

Thanks to everyone for the interest and the excellent questions! I am more than happy to do this again, please write to the Post to tell them that we want more "Ask an Astronomer" features! To learn more and NSF and the ground-based astronomy that we support, please check out this feature:

http://www.nsf.gov/eyesonthesky

 

Cheers!

- Scott

In This Chat
Scott Fisher
Scott Fisher is a Program Director in the Division of Astronomical Sciences at the National Science Foundation (NSF). Within the Division Scott oversees and manages grants in the realm of ‘Education and Special Projects’. Scott is on a 3-year detail at the NSF from the Gemini Observatory, a large, international observatory with 8-meter telescopes located in Hawaii and central Chile. Scott is a staff scientist at Gemini where he specializes in research on planet formation and does outreach for the observatory in an official capacity. He has been featured on PBS, interviewed for National Geographic magazine, and has spent over 400 nights observing on the largest telescopes in the world.
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