Wednesday, January 28, 2015

Barns Are Painted Red Because of the Physics of Dying Stars
I like articles such as this one that take mundane phenomena and link them to the stars. Though worth a read, punchline / TL;DR of this is that nuclear fusion stops generating excess energy at iron and this leads to an abundance of iron seeding the universe following supernovae, finding its way to rocky planets such as ours. Thus, iron oxide is plentiful, cheap, and just happens to make red paint.

Monday, January 19, 2015

Rare Triple Shadow Transit on January 23/January 24.

During the evening of Friday January 23/Saturday January 24 there will be a triple shadow transit. This is a rare occurrence where three of Jupiter's moons (Europa, Callisto and Io) pass between Jupiter and the Earth. For a period of time the shadow of the three moons will be visible on Jupiter's disk.

This is easy to observe with a small telescope, provided it is clear and dark at your location while the transit is taking place. For observers in the eastern United States (in the Eastern time zone) here is the timing....

Friday January 23 22:09 Callisto's shadow appears
Friday January 23 23:36 Io's shadow appears
Saturday January 24 00:03 Io begins transit
Saturday January 24 01:27 Europa's shadow appears
Saturday January 24 01:31 Callisto begins transit
Saturday January 24 01:54 Io's shadow disappears
Saturday January 24 02:07 Io ends transit
Saturday January 24 02:17 Europa begins transit
Saturday January 24 02:59 Callisto's shadow disappears
Saturday January 24 04:23 Europa's shadow disappears
Saturday January 24 04:54 Europa ends transit

(These timings are approximate, it is best to start observe a few minutes before the times indicated to be safe). Observers at other locations can adjust the time zone to determine the timings. If the sun is above the horizon at the specified time, you wont be able to see the transit.

See this article from Astronomy Now: "Jupiter’s moon dance and shadow play to delight observers:"

Thursday, January 1, 2015

Rosetta Update and Nature's 10 People who mattered this year.

Update to earlier blog post ...

The magazine Nature published "365 days: Nature's 10, Ten People who mattered this year." The first of these 10 people was Andrea Accomazzo "A former test pilot steered the Rosetta mission to an icy world in deep space."

The Rosetta mission was the first successful attempt to place a lander on a comet. Some media reports described the mission as a failure. Any media reports of a "failure" completely miss the point.

After bouncing a few times, the lander was firmly on Comet Churyumov–Gerasimenko's surface, but in a position where its solar panels will not get any light. So the lander cannot operate as expected. Nevertheless the entire mission has been mostly successful, already resulting in new insights about comets.

The Rosetta spacecraft itself has operated fine, and the lander was able to collect data for a few hours on batteries before it shut itself off due to insufficient power. Mishaps like this happen, and don't necessarily turn a mission into a "failure." Besides there is still a real possibility that the lander will be able to get power over the next few months as the angle of the sun changes.

Among other things the mission returned some beautiful photos. This picture is of the high cliffs on
Comet Churyumov–Gerasimenko taken by the Rosetta spacecraft