Eta Aquarids on their way.....

[CalliArcale]

The next predicted meteor shower is the Eta Aquarids, which is expected to peak Saturday morning. This shower is the result of Earth passing through the dust stream left by Comet Halley. The comet is currently out past Uranus, but it has littered the solar system with dust all along its orbit.<br /><br />The radiant point is in the constellation Aquarius. Aquarius is, alas, quite low in the sky for me, as I'm in the northern hemisphere. But if you live in the southern hemisphere, and especially if you are between 0 and 30 S latitude, you may get a nice show. (Northerners and those further south than 30 may still see meteors; just not as many.)<br /><br />Eta Aquarids <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[ldyaidan]

I live in Oklahoma, and it seems that every time there's a meteor shower, we end up with cloudy skies, and tons of rain, making it next to impossible to watch the shower. Is there an atmospheric relationship that causes this, or just bad luck?<br /><br />Rae

 

[CalliArcale]

Bad luck. <img src="/images/icons/wink.gif" /><br /><br />I bought a solar filter specifically to observe the last Venus transit. Guess what? It was cloudy! <img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[rfoshaug]

Why do these meteor showers radiate from the same place in the sky every year? Shouldn't the comet fragments be in solar orbit and move around a lot? <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[CalliArcale]

The fragments are scattered all along the comet's path. We experience a meteor shower whenever the Earth passes through them. It's actually an optical illusion that they're coming from the radiant point; they're not. That's actually the direction the Earth is going.<br /><br />In other words, the meteors aren't really coming towards the Earth. We're coming towards them! <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[rfoshaug]

Thanks for the info, Calli. <img src="/images/icons/smile.gif" /> <br /><br />So this means that the Earth is moving roughly toward the constellation Aquarius in our orbit when the shower occurs (so all showers seem to radiate from a point at 90° from the sun)?<br /><br />But still the fact that we move through the same path of debris from a comet at the same time every year must mean that this trail of fragments hasn't moved since last year? How can these fragments stay in the same place? Shouldn't these fragments be in solar orbit and be in a different place around the sun next time Earth runs into them (and then Earth would no longer be heading towards Aquarius)?<br /><br /><img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>But still the fact that we move through the same path of debris from a comet at the same time every year must mean that this trail of fragments hasn't moved since last year? How can these fragments stay in the same place? Shouldn't these fragments be in solar orbit and be in a different place around the sun next time Earth runs into them (and then Earth would no longer be heading towards Aquarius)? <p><hr /></p></p></blockquote><br /><br />Correct -- these are not the same fragments that were encountered a year ago. There is a very long trail of debris along the orbit of Comet Halley. (It's been in its present orbit for some time; the earliest recorded sighting was almost a thousand years ago, at the Battle of Hastings -- the comet is even depicted on the Bayeux Tapestry.) All of the debris is in heliocentric orbit, generally following a similar path as Halley itself.<br /><br />The dust trails left by comets are extremely long, and spread out more and more over time. They vary in density, as you might expect, and of course the Earth doesn't always intersect them in the most ideal way. This is what causes the dramatic variation in meteor showers from one year to the next. Astronomers try to predict intensity levels of meteor showers by estimating the density and position of the dust relative to the Earth's path, but because this dust cannot actually be seen through telescopes, it's a tricky business involving a fair amount of guesswork. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>