T9rZheTHx08 What sets the composition of nascent planets is a fundamental question in astronomy, and one that is extremely timely considering the large number of exoplanets with very different characteristics that have been discovered in the past years. Whether these planets can host life depends d...

I'm skeptical mainly of the idea that water vapor from ice vaporized by an impact could act to bring the Earth out of a snowball period.  At first glance it makes sense, because water vapor is a greenhouse gas.  But it would take a long time with a high greenhouse effect to end the snowball, and a l...

32625 I still can't work out what that line is in the top of the image, it's in all the light frames but not in the darks so I am guessing it's some reflection in the scope itself? Good question.  My first thought would have been some kind of inconsistent sensor/read noise, but if it's not in the d...

32605 I heard that snow has been making it down to sea level in Washington State! Indeed!  My view on the 15th: https://i.imgur.com/IVeEhHn.jpg Snow along the coast here isn't incredibly rare (maybe every other year on average), but usually it's more like a dusting.  On Wednesday it was 20cm, and g...

An interesting local weather phenomenon is about to strike my area -- the Fraser gap wind (also sometimes called outflow winds or  squamishes ). When cold arctic air comes down out of Canada, it gets dammed up on the east side of the Cascade mountains, except at narrow terrain gaps like fjords, and ...

32540 the compulsive thinking in climate science: "If obsvervations don't exist, there must be a way somehow to reconstruct them". The actual and reasonable thinking is: "If direct observations do not exist, then do there exist methods for reconstructing them by correlations to other...

32529 The observational astronomy text you listed is also highly interesting because it mentions photometry and spectroscopy and how to do scientific research with CCD cameras. Yes, this is what "observational astronomy"  means  nowadays. :)  The difference between it and casual observing...

32520 Is it good for observational astronomy too?  I'm not sure if you're using  observational astronomy in the technical sense?  Almost everything in it is based on observational astronomy, because without observations and data, this would not be a science.  But it doesn't much discuss the details...

Hi  szymas , I think a good fit for you would be the text  Universe: Stars and Galaxies  by Freedman and Kauffmann.  The text gives an overview of most broad topics of astronomy, from its origins with ground-based observing and the function of telescopes, to the planets and solar system, stars (thei...

32511 Wat, what caused that?  Dry weather and high winds? Pretty much.  There's not much snowpack over there right now to hold them down, and a big windstorm just blew 'em all over the place, blocking highways and burying cars. Parts of Australia are obviously dealing with much bigger problems righ...

Meanwhile in eastern Washington, an unusual weather phenomenon was observed.  Tumbleweed storm.

One last rockhounding trip to finish the year.  Southwest Washington has some of the biggest and best carnelian I've ever seen.

32412 Speculations that this is a sign of imminent supernova are - highly speculative. Quite.  It is a variable star, and we don't know if (or even expect, really) obvious changes in its brightness would correspond to changes in its core fusion processes.  I liken it to all the buzz that happens in...

Beautiful lighting.    Today my color has been green.  Green chrysoprase that is, collected from a nearby creek.  Today I worked on some pieces with a diamond cutting wheel.