11
$\begingroup$

As per the title, I'm curious about technologies that would detect previously unknown objects like the Chelyabinsk Meteor as they enter the atmosphere. An answer that could satisfy some or all of the questions below would be ideal.

  • Is there technology that is explicitly deployed for this task, or do we retrieve data from unrelated sources like seismographs or radar?
  • What sort of data is collected about the object?
  • Would their data have any lead time as compared to observations from people on the ground (even a very small leadtime)?
$\endgroup$
3
  • 1
    $\begingroup$ Missile defense folks (both space (IR) and ground (radar) segments); amateur astronomers. $\endgroup$ Aug 23, 2013 at 17:14
  • 3
    $\begingroup$ BTW, why do you need lead time? If a big chunk of rock is flying at you and you detected it only in the upper atmosphere, there's precious little you can do: say a prayer, call your relatives. That's it. $\endgroup$ Aug 23, 2013 at 17:23
  • $\begingroup$ @DeerHunter That part of the request was more academic than practical in nature. I was simply curious if there was any measurable or expected difference. $\endgroup$ Aug 23, 2013 at 19:21

1 Answer 1

3
$\begingroup$

NASA defines meteors as:

The light phenomena which results when a meteoroid enters the Earth's atmosphere and vaporizes; a shooting star.

So we'll stick with that (besides, meteoroids are generally too small to track otherwise, and the ones that are big enough to track are referred to as asteroids anyway). If you are interested in asteroid tracking, NASA's Near Earth Object Program has got you covered.

The American Meteor Society maintains a system for reporting "fireballs" and "bolides" - both terms for meteors that are bright enough to be seen from a very wide area. The link has a very good discussion of the details of this system, but a particularly interesting chart showing the number of event reports collected by the AMS is below.

AMS trends

They note that in 2010 the system was upgraded to a "database Google maps" system, which made it much easier for people to file reports (thus the drastic increase). They classify events by the number of reports received, ranging from "Unconfirmed" (reported by only 1 witness) to "Huge" (100+ witnesses). They also have a special class for fireballs large enough to produce a sonic boom (as confirmed by 2 or more witnesses).

Space-based sensors owned by the U.S. Government (namely IR sensors) are able to detect and report particularly bright fireball events (the sensors are typically meant to detect space/missile launches). As the AMS article notes, the U.S. recently decided to start sharing data on fireball events. NASA has set up a website for sharing these reports with the public. According to this, reports generally include position (latitude, longitude, and altitude, presumably at the peak brightness point), date/time of peak brightness, velocity, and the estimated radiated energy (from which NASA can estimate the total impact energy).

Presumably, events like this are picked up on ground-based sensors (such as radar) typically used for space surveillance, but this data does not appear to be reported. One main reason for this is that it's probably difficult to even confirm that the detected object was in fact a meteor.

As far as lead time, there is really nothing significant to speak of, since the detection can only happen once the object begins interacting with the atmosphere.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.