meteorites

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Meteorite shower tonight, does anyone know when to look for these ?

muckish

To be pedantic... It's a meteor shower. They are only called meteorites if they survive the burning up in the athmosphere and make it to Earth's surface.
Tonights shower is called the Lyrids, and should radiate from the bright star Vega in the Northeast.

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muckish wrote: »

To be pedantic... It's a meteor shower. They are only called meteorites if they survive the burning up in the athmosphere and make it to Earth's surface.
Tonights shower is called the Lyrids, and should radiate from the bright star Vega in the Northeast.

Thanks, some people have to learn by their mistakes. I was out and saw nothing, but then my range of visibliity to the NE was restricted.

k.p.h

I was out there for 20 min just nom and saw nothing either I presume it should still be from the direction of Vega. I make that to be in the East right now. Not sure really .? Should I be seeing some..

gugsy

cloudy with showers in galway cant see anything yet the shower activity is at its maximum tonight between 11pm and 6am

battle_hardend

pissing rain here , cant see a thing in the sky :mad:

Super-Rush

Best time to see them will be from now until daybreak.

You're only going to get 10-15 meteors per hour.

MeteoritesEire

I was out looking 2 nights ago and didn't see any --sky was partially cloudy though but the southeast view to Lyra was clear.Cloudy last night.

I have some small meteorites for sale if anyone interested.From the Sahara desert Morocco/Algeria--see my adverst ads

Bawnmore

Would it be right to assume the next possible shower will be Eta Aquarid on the 5th/6th May? It looks like there'll be a full moon out that night too though, so is there any chance of seeing something?

jfSDAS

hi Bawnmore,

The info from my May sky notes post is below -- it never gets truly dark at any stage this May 5th so you will only see a handful of eta Aquarids.

An important factor is the ZHR, or Zenithal Hourly Rate. This is the theoretical number of meteors seen in an hour and is based on a Moonless sky, stars visible to magnitude 6.5 (the unaided eye limit), the radiant source overhead, and no meteors missed. The ZHR is based on a formula applied to what you actually see in an hour of watching.

The true number of meteors seen is always much lower than the ZHR -- I was astonished at the amount of publicity given to the recent Lyrids. A number of sources gave the impression people just had to step outside and see meteors "blazing" across the sky. That is just going to disappoint when a hyped up astronomical event fails to live up to its billing.

When the 1899 Leonids failed to put on a major display after scientists predicted a major storm, it was said at the time that astronomy suffered its worst blow in the eyes of the public. Sometimes I think the lesson hasn't been learnt :eek:

An interesting site besides the ones quoted below is http://www.amsmeteors.org/2012/01/2012-meteor-shower-list/ which explains some of the terms in meteor astronomy.

clear skies!

john

The Eta Aquarids reach a peak on May 5th/6th but the radiant (point of origin of the meteors) is low from here and only at a useful altitude in the pre-dawn hours. With maximum this year falling on the day of Full Moon you’ll be hard pressed to catch more than a handful of the brighter Eta Aquarids. The shower is associated with Comet 1P/Halley. On occasions Venus fords the meteoroid stream at the same time as we do and at these times we can imagine a tenuous bridge of particles connecting the two worlds. Details of meteor showers during the year can be found at http://meteorshowersonline.com/calendar.html or http://www.imo.net/calendar/2012

Bawnmore

jfSDAS wrote: »

hi Bawnmore,

The info from my May sky notes post is below -- it never gets truly dark at any stage this May 5th so you definitely should just see a handful of stream members.

Thanks John - do you mind if I ask what you mean by "stream members"?

jfSDAS

no problem to explain "stream members" ... you'll see though that I've taken the term out of my original post as some sentences were originally written in haste!

A meteor shower is caused when the Earth encounters a stream of meteorid particles laid down by a comet along it's path around the Sun. These particles can range from micron size to small pebbles with the rare fist-sized object.

When we plough through this stream the particles enter our atmosphere and burn up, which we see as a "shooting star" or meteor. The higher density of meteoroid material in a stream is what gives rise to a meteor shower, but also the fact the particles are travelling in parallel through space -- the effect of perspective though makes them appear to diverge from a single point in the sky when you trace their paths back. It's the same effect as parallel railway lines receding in the distance.

The particles in a newly produced stream can be mixed but over time they will be sorted so that similar sized objects will travel along the same "ribbon" within the stream -- what is called mass-sorting. This will also lead to a concentration of material at the centre of the stream that tails off at the edges, which is why a shower builds in intensity and then the rates decline.

The structure of meteoroid streams can be quite complex and several "ribbons" of material can give rise to more than one peak in a meteor shower. For example, the well-known Perseids in mid-August had a double-peak a few years ago but this has now contracted to a single maximum.

Another factor, hinted at above, is the age of the stream. The parent comet of the Perseids has made numerous passes around the Sun and the material shed by the comet has spread evenly around the comet's orbit. This is why the Perseid rates are pretty similar year after year -- though the rates climb somewhat when the comet is in the inner solar system.

The November Leonids on the other hand are a young shower and the material has not spread evenly around the parent comet's orbit. You get clumping of material near the comet and every 33 years we encounter these clumps giving rise to storm rates (approx >1000 meteors per hour). The last Leonid storms were around 1999 and next expected in 2032.

Streams can also get disrupted by gravitational encounters with the planets (especially with Jupiter) and may eventually miss Earth altogether or be encountered by us for the first time.

Finally, if a meteor is sufficiently big enough it will survive its fiery passage through the atmosphere and fall to the ground as a meteorite.

Meteoroid (outside our atmosphere), meteor (a "shooting star"), and meteorite (when it hits the ground!)

A great introduction to the history of meteor astronomy is Mark Littmann's "The Heavens on Fire" while the resources on the IMO page http://www.imo.net are excellent -- the IMO are the world coordinating body for meteor observations.

all the best,

john

MeteoritesEire

just to add to jfSDAS' info above which is good, if you are in a good dark sky spot such as I am fortunate enough to be in , in Western Donegal you can also see a dozen or more meteors an hour on any clear night which are known as 'sporadic's .They can originate from literally anywhere in the sky.Also I can spot probably about the same number, a dozen or so satellites per hour.There's a website for tracking them for those so inclined.

jfSDAS

cheers for that info on sporadics and satellites MeteoriteEire (that's a great boards name btw!) -- I had a look at the samples for sale and am tempted.

atb,

john

MeteoritesEire

thanks John-that was some good info from yourself too my friend.

I'm about to overhaul my adverts ads as that one meteorite ad I have had running for ages does tend to confuse some people-it's a bit of a mash-up.I'm going to make things much more clear with individual pictures in the very near future.Careful though,once you start with one meteorite it can get a wee bit addictive haha--I remember my first back in about 1995--mind literally blown

Jim