Meteor shower

[HacksawParticipant @hacksaw]

These here shooting stars I'm watching …. why do some ( most ) appear to be going north to south and others west to east or the odd random ? I picture Earth going though a load of debris at thousands of m.p.h. so they ought all to appear going one way ?

[HacksawParticipant @hacksaw]

[duncan webster 1Participant @duncanwebster1]

Chucking it down here so I can't see them, and now I have to walk the dog

[John OlsenParticipant @johnolsen79199]

What you are seeing is the Perseids shower. Usually a shower like that will appear as if the meteors are all coming from one point in the sky, in this case somewhere in the Perseids constellation. The apparent point of origin is called the radiant, and a long exposure photograph will show the tracks all pointing away from that point, with possibly the odd other track from some unrelated particle entering the atmosphere.

Of course the meteors are not coming from the actual stars in the constellation. They are probably the remains of an old comet and after it breaks up they end up strung out along the old orbit. So they all tend to arrive from roughly the same direction and in this case, that direction is from the direction of the Perseids constellation. It is a bit like when the sun is shining around the edges of a cloud, the rays are effectively parallel but look like they are all radiating out from one point.

We were out in the spa pool last night, and I did see one meteorite, but of course have no way of knowing if it was part of the Perseids shower, or a random particle, or even a piece of space junk. But we have been out there while showers were occurring. It is quite a nice way of doing naked eye astronomy! I was a bit mystified by some flashes we were occasionally seeing for a while, until I found out about Iridium flares.

John (in NZ)

[Neil WyattModerator @neilwyatt]

There are always some random meteors on any night, but as John says most of them would have 'traced back' to Perseus.

I only saw about six or so, but one was very bright and made a distinct fizzing/whooshing sound. I dismissed this as my imagination, but it turns out that hearing big meteors isn't unusual. The theory is that the huge emission (megawatts) of low frequency radio is enough to make grass, leaves etc. vibrate!

Neil

P.S. reason I didn't see more was I was watching a 'guiding graph' on my computer. I put the data towards this:

[Russell EberhardtParticipant @russelleberhardt48058]

Good view here from the top of Forca Real (500 metres elevation)

Russell

[larry PhelanParticipant @larryphelan54019]

I thought I saw a few odd lights a few nights ago,but I was wrong,it was only the after effect of a bottle of good wine !

Must try it again soon .

[RobboParticipant @robbo]

Don't mention the meteor shower. I've been out looking for it and the sky has always been cloudy, except sometimes it was pouring with rain.

[Andrew TinsleyParticipant @andrewtinsley63637]

For once the sky was clear and I had a spectacular seeing session. With respect to hearing meteorites, I had a really interesting meteor sighting when I was about 10. I was walking home one Sunday night with my mother, when I heard a most unusual rumbling sound. Looking up, I saw a fireball slowly traversing the sky. It appeared to move in some sort of cycloid motion. The whole thing lasted for maybe 20 seconds or so and then disappeared from view behind some buildings. Tuesday's paper had a report of this large meteor and experts said that it landed in the Atlantic a few hundred miles from the coast. The rumbling sound was quite loud, so you can hear meteors, but probably not very small micrometeorites that burn up in the upper  atmosphere. The ones that are big enough to reach the more dense atmosphere can certainly be heard.

Andrew.

Edited By Andrew Tinsley on 15/08/2017 15:45:44

[MikeParticipant @mike89748]

I think it was in the late 60s or early 70s that I saw and heard a very large meteor. It was like a flaming football crossing the sky roughly from south to north. Apparently it crashed into the sea somewhere north-west of the Hebrides. I made the observation from the wheelhouse of an angling charter boat moored in the estuary at Rhyl, and when Patrick Moore asked for news of sightings on his Sky at Night programme I was able to give him a reasonably accurate report thanks to the boat's compass. Could this be the same meteor as observed by Andrew?

[Neil WyattModerator @neilwyatt]

This is what Wikipedia says. I'd already posted that I heard one but must have imagined it on another website before finding this and some NASA information on the subject by accident:

Acoustic manifestations

Sound generated by a meteor in the upper atmosphere, such as a sonic boom, typically arrives many seconds after the visual light from a meteor disappears. Occasionally, as with the Leonid meteor shower of 2001,"crackling", "swishing", or "hissing" sounds have been reported,^[45] occurring at the same instant as a meteor flare. Similar sounds have also been reported during intense displays of Earth's auroras.^{[46][47][48][49]}

Theories on the generation of these sounds may partially explain them. For example, scientists at NASA suggested that the turbulent ionized wake of a meteor interacts with Earth's magnetic field, generating pulses of radio waves. As the trail dissipates, megawatts of electromagnetic power could be released, with a peak in the power spectrum at audio frequencies. Physical vibrations induced by the electromagnetic impulses would then be heard if they are powerful enough to make grasses, plants, eyeglass frames, and other conductive materials vibrate.^{[50][51][52][53]} This proposed mechanism, although proven to be plausible by laboratory work, remains unsupported by corresponding measurements in the field. Sound recordings made under controlled conditions in Mongolia in 1998 support the contention that the sounds are real.^[54] (Also see Bolide.)

[Clive HartlandParticipant @clivehartland94829]

I sailed across the Atlantic in 2004 and my watch was from 2000 to midnight. The sky was as I remember it as a child with no ambient light. We were about 500 miles North of the Cape Verde Islands.

The Milky way was clear and sharp and, I was laying on my back dozing (Bad) and there was a glow in the sky and a small Meteor came down almost vertically about a half mile from the Yacht, it extinguished on entry into the water but I heard no sound. Anyway I am very deaf.

The dawns and sunsets were perfect and I can remember seeing the Moon setting and the Sun rising at the same time. The clouds often showed low cloud going one way and higher cloud going the opposite way! We followed a trail of wine bottles floating neck up for about two days, must have been a good party!

Clive

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello Mike,

The meteor that I saw, was about 1954-55. It was obviously tumbling and the aerodynamics of the thing were no doubt responsible for the tumbling , cycloidal flight path. It was a very slow moving object compared to a normal meteorite. It must have been a big beast.

Andrew.

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello Mike,

The meteor that I saw, was about 1954-55. It was obviously tumbling and the aerodynamics of the thing were no doubt responsible for the tumbling , cycloidal flight path. It was a very slow moving object compared to a normal meteorite. It must have been a big beast.

Andrew.

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