Photon: stars

Showing posts with label stars. Show all posts

Monday, June 25, 2012

Winter cone

The famous Cone Nebula can be found in the constellation of Monoceros and it's one of those star forming factories in our galaxy which already created a very young star cluster (the Christmas tree, NGC 2264 :) ). S Monocerotis is responsible lighting up the last remains of the "mother - gas cloud". 7 light years across (10 arcminutes) and 2700 light years distant, the Cone Nebula is part of a huge star forming complex in the winter skies, a blend of dark and excited gas and dust clouds.

I have always wished for a Christmas Tree like this.

Monday, May 21, 2012

Peak District: cold, night, spring

Twilight arrives finally in UK's Peak District National Park. Charged with color beauty, Venus trails along the Pleiades on it's journey away from the Sun: it is the last time it goes away from it before the famous Venus transit this June (more about that soon!).

Even though it's cold, some people do look up, through the dense photon cloud of light pollution

The road to light below us (it was oriented towards West :) )

... and he stands below all that is timeless for most humans: stars!

Wednesday, May 2, 2012

Crab nebula and polarized light

Besides wavelength (color), photons have other properties too: if seen as a wave their electric field oscillates in a plane which can remain fixed or rotate in time and by convention we describe this polarization state by specifying the orientation of the electric field over one oscillation.

Polarimetry is a very useful tool for determining what kind of physical processes are at work in the light source (especially for synchrotron radiation) and the distribution of magnetic fields in it: there is much more to light than just color!

Polarimetry color information superimposed on a "normal" photograph of Crab nebula creates the unusual picture below. The red color in the nebula comes from an arbitrary initial polarisation angle (we weren't able to find out yet the true polarizing angle), the green shows 45 degrees more and the blue is with the filter rotated by 90 degrees compared to the original position.

Earth Science Picture of the Day for June 24th 2012.

The image has been made by me (color and luminance data) and David Muelheims (polarized data), in Bonn, Germany.

And although "popular wisdom" might tell you that the human eye cannot distinguish between polarization states, it's not really true, as Haidinger found out many, many years ago :)