Category: Science

Why Planets Have Which Atmospheric Gases


The image associated with this post is a slide taken from a MOOC called BUx: ASTR105x Alien Worlds: The Science of Exoplanet Discovery and Characterization offered at EdX. What it shows is the speed of various gas molecules at various temperatures. These are shown at lines showing the speed the molecules move at those temperatures. Notice that heavier gases move slower at a given temperature but all increase at a similar rate as temperature increases. Also plotted on the chart are various solar system objects at their temperature and on their escape velocity. A planet will hold all the molecules which are moving slower than the escape velocity of the planet at the planets temperature for as long as the solar system exists. Gasses above that will eventually drift away.

I just found this graph to interesting to pass up.

Cosmic Coathanger


The asterism called “The Coathanger” is a fun thing to find with binoculars at night.   I’ve looked at it more than once.   I’ve never seen it so beautiful though as here.  The colors are stunning.  This was displayed over at APOD on August 26th.

There really are cellular level fossils… cool !

Rhynia gwynnevaughanii,

Rhynia gwynnevaughanii, transverse section of a stem with diameter 1.3 mm. Rhynie (Scotland). Lower Devonian (408 million year).

I recently read an article in National Geographic about the discovery of 50 Million Year Old fossilized worm sperm.   I’ve seen other items about cells that have been individually fossilized.   I simply found the idea incredulous.  I questioned if minerals and rocks really could preserve that level of detail.   Today I decided to google a bit and see what kind of stuff was being claimed as found.

There are a number of fossilized plant stems which have been cross sectioned.   The one here in this is just one example.   Rhynia gwynnevaughanii and it pretty well lays to rest any questions one might have.   The cellular structure is so clearly visible it is amazing.  It looks like those initial slides you look at when you get your first microscope

4.4 Billion Year Old Oceans ?!?!?!

Reading about meteorites I began to look into the high water content of carbonaceous chondrites.   It is alleged these can reach 22% water.   This eventually led me to discover the Jack Hill Zircon.   These little rocks have apparently been causing a ruckus for a while now.   It caused NASA to allow the following words to be uttered ….

Since then, however, scientists have found zircons that date to almost 4.4 billion years ago.

Among the first important discoveries, says Watson, came out in 2001. Analysis of the relative amounts of different isotopes of oxygen indicated that the ratio was skewed toward “heavy” oxygen-18, as opposed to the more common “light” oxygen-16. “When a geologist sees a heavy oxygen signature in rocks,” said Watson, “it’s commonly understood to be a sign that the rocks formed in cool, wet, sedimentary processes at the Earth’s surface.” Thus, the magma that eventually gave rise to the zircons might have been formed from what had once been sediments deposited on the floor of an ancient ocean.2006 NASA Earth Observatory

Now I am still trying to get my head around that last sentence given everything I’ve been taught about the formation of the earth from a scientific view.   Really the number of ways that causes mischief are hard to fully discern initially.

Runaway Stars and Bow Shock

Today I was looking into run away stars.  These are stars moving at high speed unrelated to the stars of their surroundings.  They are just off on their own and not swimming with the other fishes so to speak.   In some cases these stars wind up plowing through existing nebula clouds.  When they do they distort the existing clouds.   To an astro nerd like me … its pretty cool.

Zeta Ophiuchi — via JPL, Caltech SPITZER

Above is Zeta Ophiuchi.  This particular bow shock distortion is stated to be 0.5 light years from the star.

Kappa Cassiopeiae, SPITZER infrared

Above is Kappa Cassiopeiae,  This is said to be a bow shock at a distance of 4 light years.  Which is, to me, really awesome.

Airbus vs SpaceX

Airbus has a novel approach to reusable spacecraft.   Its still essentialy a design concept, a full size version hasn’t been built yet, and so is far behind Space X.

The nut of it seems to be preserve the expensive parts like the motor and avionics while throwing away the tanks.   This lightens the amount to be returned, reduces fuel costs as a result.  The returning section sits at the base of the booster, essentially returns as a glider and appears to use some form of propeller driven flight for the final leg to the landing strip.  Space X by comparison tries to return the entire booster under rocket power to the launch pad.   This requires substantially more fuel [ cost ] and also has yet to actually work.

In theory Space X is more reuseable because their whole booster lands not just the base of the booster.   But from a cost and economic impact it may require more resources, time will tell.

Ceres Up Close

NASA Dawn is giving us some great footage of Ceres.   Still lot of fun questions with the bright spots in that crater.   Maybe Tom Bodett left the light on for us.