The Size of a Meteor

According to television news, these specks are simply dust-sized, though they are travelling at such high speeds that the air through which they pass is heated to extremely high temperatures. What one sees in the sky is the glow from all the high-energy air as it cools down again.

Anything as big as a school bus would probably reach the surface and cause substantial damage. And a sky scraper? Well, wheel in Bruce Willis quick!

Some bigger ones have reached the surface. The Ventersburg one created a arc of mountains about 100km-120km away. Parts of big ones can still be seen. (Namibia etc).

The moon was apparently formed when a mars size objects hit the earth. (slightly before my time).

I personally think that pea size ones are also common.

These things keep me awake.

Nice to meet you Pete Traditional

I have an observatory on my property, housing an 8 inch and a 10 inch (newtonian reflectors).

I am out every night that is clear, this weekend was fairly good but the Persiad meteor shower was less than I had hoped for. As I write this, I have just come inside from observing.

To answer your question... meteors are debris blown off of comets by solar radiation (for the most part) and are typically dust size. Meteors of salt grain size can be pretty spectacular, leaving a visible trail, somewhat greenish but mostly white.

Larger meteors, say softball size or larger would be like a fireball streaking across the sky making noise as they burned up.

As for school bus or sky scraper, I'm thinking mass extinction time!

Thank you! Now I understand that what we see is not the actual piece of the meteor, but rather the termoil it causes as it flys through space. I was up in Northern SK a couple of years ago, and got to see the Northern Lights (I can't spell their real name.) Spectacular sights out there. Thanks for your time and help. --David

http://en.wikipedia.org/wiki/Aurora_%28astronomy%29

Dust size, pea size..., HEY! This is a science and engineering site. Who can cite an experiment that has captured and measured these particles?

Bob

I have personally heard two meteors coming down. both at night on different occasions. Both bright green lights that lit up all of the surrounding desert that left long lines of smoke in the sky.

No measurements were made. I think I was just standing there with my jaw hanging open.

-A-

I was just standing there with my jaw hanging open

I'd be looking for clean underwear.

Many investigators believe the sounds to be imaginary... essentially sound effects added by the mind to go along with a light show. However, the persistence and consistency of the reports have caused others to wonder.

In both cases I was looking down when I first heard the hiss and saw the ground around me lit up with a weird green glow. The sound came from straight up, so that's where I looked, just in time to see about the last half of the meteor. The smoke trail persisted for some time. I think maybe a full minute. At the time I supposed I was able to hear it because it was low in the atmosphere.

Strange that there would be some debate over something that happened to me not once, but twice. Maybe those researchers should move out to the Mojave desert.

-A-

Hello -A-,

What you experienced were meteorites.

Just for the fun of it, here's some clarification of sizes from Wiki:

"A meteoroid is a small sand to boulder-sized particle of debris in the Solar system. Larger than that, the object is an asteroid; smaller than that, it is interplanetary dust. The current official definition of a meteoroid from the International Astronomical Union is "A solid object moving in interplanetary space, of a size considerably smaller than an asteroid and considerably larger than an atom or molecule." The Royal Astronomical Society has proposed a new definition where a meteroid is between 100 µm and 10 m across. ^[1] The NEO definition includes larger objects, up to 50 m in diameter, to this category.

A meteor is the visible event that occurs when a meteoroid or asteroid enters the earth's atmosphere and becomes brightly visible. For bodies with a size scale larger than the atmospheric mean free path (10 cm to several metres) the visibility is due to the heat produced by the ram pressure (not friction, as is commonly assumed) of atmospheric entry. Since the majority of meteors are from small sand-grain size meteoroid bodies, most visible signatures are caused by electron relaxation following the individual collisions between vaporized meteor atoms and atmospheric constituents. The meteor is just what we see.

A meteorite is a portion of a meteoroid or asteroid that survives its passage through the atmosphere and impact with the ground without being destroyed. Meteorites are sometimes, but not always found in association with hypervelocity impact craters; during energetic collisions, the entire impactor may be vaporized, leaving no meteorites".

-John

Good descriptions and excellent references. Thanks for all readers.

Just one futher note... as for bus to sky scraper sized meteors... I dont think they are all that uncommon on a geological time scale... the largest of such have believed to end the dinasour dynasty while smaller but still significant sized meteors have left landmarks like crater lake in Oregon... Not so convinced that life as we know it would end if a bus sized meteor entered our atmosphere... besides i think the majority of a bus sized meteor would incinerate in the atmosphere...

Crater Lake was formed when a volcano collapsed, not by a meteorite. At least that is what is stated on the website.

Tas

How big is big?

"It depends on what the definition of IS is" - Former Pres. Clinton.