Astronomy

Posted by colby

Older news from the Orbital Debris Quarterly News, Volume 12, Issue 1, January 2008:

Early impact test results suggest that the particle size was approximately 1.5mm to 2.0mm in diameter, assuming that the particle was orbital debris.

An impactor, maybe 1.5-2.0mm wide, creating a hole ~1⁄3 in wide through thin layers of an aluminum honeycomb radiator and silver teflon tape.

Posted by colby

Indirect evidence is the life blood of astronomy as a science. When gauging the distances between our star---the sun---and objects we see in the sky, direct methods only work out to about 300 light years.

By direct measurement, I mean the use of a physical or geometric change (such as the Earth orbiting around the sun once a year) to measure a change in the position of stars as seen from the Earth. Take a picture of the stars in June, then another picture of the same stars in December, compare the results; knowing the distance the Earth has travelled, you can compute distances to stars, gas clouds or dust, directly. The primary limitations are how small are the changes in apparent position of objects in the sky that can be measured (in arc-seconds) and the distance the Earth has traveled (in millions of meters). If you've heard the term, parsec, it is named after this direct method of measurement, and is short for the parallax of one arcsecond.

300 light years is not very far on the scale of what we see in the universe. Our galaxy, The Milky Way, is estimated to be over 100,000 light years across. The nearest large galaxy outside of our own, 2,000,000 light years or over 600,000 parsecs away.

chromoscope

09 Dec 2009
Posted by colby

credit: chromoscope

The Milkyway in 6 different wavelengths.

Chromoscope

Posted by colby

credit: NASA

As noted on the mission pages for the Lunar CRater Observation and Sensing Satellite (LCROSS), the team has posted data that indicates they have found water at the southern pole of the moon, LCROSS Impact Data Indicates Water on Moon

During the 4am local time of the impact, Samantha Blair, a visiting researcher from the SETI Institute was taking data while I got up to make sure the telescopes and backends were functioning properly and offer a hand should a problem crop up just before the observation.

The ATA observation was acquired at 1.666GHz, with 6.5MHz of bandwidth to look for spectra corresponding to OH emission and you can see detailed notes from the observation on the HCRO LogBook, LCROSS quick check reduction from that data taken during the impact.

The field of view at 1.666GHz is about 4 times the size of the moon. You can see why this is true if you go back to the relationship of field of view or "beam width" to the frequency being observed over the diameter of the telescope involved, or: F = λ / d

Missions to Mars

23 Oct 2009
Posted by colby



This little info graphic morsel is from Shnell dot com and shows a history of missions to mars: