APOD 4.1-Rocket Trails in the Milky Way

On the 27th of March, five rockets were launched from NASA's Wallops Flight Facility in Virgina. The Anomalous Transport Rocket EXperiment (also known as ATREX) began launching at 4:58 am and launched these rockets at 80 second intervals. The chemical tracer that comes out of the rockets releases white clouds within Earth's ionosphere. These cool clouds were seen along the mid-atlantic region of the U.S. as the clouds drifted across the starry sky. This magnificent photograph was captured in New Jersey and the constellations visible in the background include Sagittarius and Scorpius, but also visible is the Milky Way.

APOD 3.9- Jupiter and Venus from Earth

Last week Venus and Jupiter were both visible in sunset conjunction to anyone in the world. If you had a clear western horizon you could see them. This week they are both still noticable but Jupiter has sunk below the brighter Venus. In the picture above, taken in Poland, you see the close approach of the two planets taken a week ago. The bright planets were only separated by 3 degrees. A faint red sunset still appears to be glowing in the background. Another conjunction similar to this will occur in May.

Supernova Remnants

A supernova remnant is the structure resulting from the explosion of a star in a supernova. There are two possible routes to a supernova: either a massive star may run out of fuel, ceasing to generate fusion energy in its core, and collapsing inward under the force of its own gravity to form a neutron star or a black hole; or a white dwarf star may accumulate material from a companion star until it reaches a critical mass and undergoes a thermonuclear explosion. One of the best observed young supernova remnants was formed by SN 1987A a supernova in the Large Magellanic Cloud that was observed in February 1987. Other well-known supernova remnants include the Crab Nebula.


A Supernova Remnant goes through these phases:
1. Free expansion of the ejecta    2. Sweeping up of a shell of shocked circumstellar and interstellar gas
3. Cooling of the Shell                 4. Cooling of the interior
5. Merging with the surrounding interstellar medium

There are various types of Supernova Remnants including:
-Shell like, such as Cassiopeia A
-Composite, in which a shell contains a central pulsar wind nebula, such as G11.2-0.3 or G21.5-0.9
-Mixed-morphology