Sep 1, 2010

Posted by in Physics Talk | 2 Comments

Astroid Fever – astroid density in the solar system


Of course one knows about the astroid belt, but it has never been visualized as clearly as this image and the compendium video shows.

Click for a better view or visit Current Map of the Solar System

The terrestrial planets (Mercury, Venus, Earth and Mars) are shown on the diagram by Cyan or White squares, and their orbits are represented by the blue ellipses around the Sun (the yellow dot at the centre). The Earth is highlighted because of its special importance to us. Small green points mark the location of asteroids which do not approach close to the Earth right now. This does not exclude the possibility that they will do so in the future but generally we can consider the Earth to be safe from these for the near future. Yellow objects (with the exception of the one in the middle which we astronomers call the Sun ;-) are Earth approaching asteroids which are called Amors after the first one discovered. Amors have orbits which come close to the Earth but they don’t cross the Earth’s orbit. However, their orbits are close enough to the Earth that they could potentially be perturbed by the influence of the planets and begin to cross the Earth’s orbit in a short time. There are over 300 known objects on such orbits.

It is estimated that there are perhaps 100,000 to 1,000,000 undiscovered asteroids on similar Earth crossing orbits.

And here is a video of astroids as they are discovered over the last 30 years. If you prefer, you can view the last 30 seconds to see the current known density of the astroids. I am sure additional astroids will be discovered but I suspect the density map will probably remain the same.

Notice now the pattern of discovery follows the Earth around its orbit, most discoveries are made in the region directly opposite the Sun. You’ll also notice some clusters of discoveries on the line between Earth and Jupiter, these are the result of surveys looking for Jovian moons. Similar clusters of discoveries can be tied to the other outer planets, but those are not visible in this video.

As the video moves into the mid 1990′s we see much higher discovery rates as automated sky scanning systems come online. Most of the surveys are imaging the sky directly opposite the sun and you’ll see a region of high discovery rates aligned in this manner.

At the beginning of 2010 a new discovery pattern becomes evident, with discovery zones in a line perpendicular to the Sun-Earth vector. These new observations are the result of the WISE (Widefield Infrared Survey Explorer) which is a space mission that’s tasked with imaging the entire sky in infrared wavelengths.

Currently we have observed over half a million minor planets, and the discovery rates snow no sign that we’re running out of undiscovered objects.

Thank You Scott Manley for making this video – astroid belt has never been so real to me.

  1. neat, Sunny! there’s also a fun (to my mind, anyway) 3D model of those half-million minor planets in Microsoft Research’s “WorldWide Telescope” app. I posted a . (full disclosure, I work at Microsoft.)

  2. neat, Sunny! there’s also a fun (to my mind, anyway) 3D model of those half-million minor planets in Microsoft Research’s “WorldWide Telescope” app. I posted a pretty picture at . (full disclosure, I work at Microsoft.)

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