国家地理-2008-03-20 Rho Ophiuchi Cloud 璀璨的星云（在线收听）

Rho Ophiuchi dark cloud is one of the closest star-forming regions to our own solar system. Located near the constellations Scorpius and Ophiuchus, the nebula is about 407 light years away from Earth.

The infrared astronomical satellite, now celebrating its 25th anniversary, gave us the first all sky view of our dusty infrared universe. Floating above the galactic center is the Rho Ophiuchi Cloud, about 400 light years away. It's one of the most spectacular nearby star-forming regions. NASA's Spitzer space telescope has now given us an impressive new view of this cloud's central core.

Compact yellow green arcs and filaments are shock fronts from proto-stellar jets within the cloud. These jets shoot out from young stars still growing as they gobble up the surrounding dust and gas. Here we see infrared light with wavelengths from 3.6 to 8 microns. Widening the coverage to include 24 microns yields an even richer array of colors that shed light on the temperature and composition of the dust here.

The cloud is named after the nearby star Rho Ophiuchi which ironically is not thought to be associated with the star-forming region, and does not appear in the Spitzer image. Also known as Lynds 1688, this region contains over 300 baby stars with ages of up to a few hundred thousand years. The dusty envelopes around the younger stars make them appear red in this rendering. In visible eye, they can't be seen at all, which is why astronomers rely on Spitzer's infrared perspective to help study the hidden universe.

1. infrared : adj.  红外线的

of or being rays of light of long wavelength that cannot be seen but give heat.

 2. galactic : adj.

relating to a galaxy

 3. filament : n.

 a very thin thread or wire; e.g. an electric filament

 4. shock front :

The boundary between the pressure disturbance created by an explosion (in air, water, or earth) and the ambient atmosphere, water, or earth.

 5. gobble up :

to eat something very quickly, especially in an impolite or greedy way

 6. yield : v.

to produce a result, answer, or piece of information

 7. proto- : esp. tech

first in time or order, especially having others come after it or develop from it; original

e.g. protostellar, protogalaxy