out of the box viewing

I had a delightful chat with Juliette the other night and fell into talking about astronomy.  The next day I came across an image that is a beautiful representation of this and sent it to her along with a bit of an explanation.  The lead in was we were talking about brown dwarf stars the night before - amazing objects that are borderline stars.  They can be very cold - in fact one has been discovered with a surface temperature a bit lower than your skin temperature!  That makes them approximately difficult to detect and they were theoretical until fairly recently, but very sensitive orbiting infrared detectors now detect them and, as you often learn when stumbling onto a new beach, there are puzzles that we hadn't imagined.   One is there are too many for current theories of stellar formation to explain.  Such a lovely problem.

 

I'm very impressed at how small our access is to the Universe if we just use our five senses.  They have serve us well and most of us get along well without enhancing them, but amazing advances in science have been made when we open up new views of Nature.  For a few hundred years telescopes made the dim bright enough to see and then to photograph, but an enormous explosion of new questions and a deeper conversation with Nature came when we started to look at wavelengths beyond what we normally see.

 

Here is the note I just sent with non-astronomy parts edited out - nothing like killing two birds with one stone.

 

 

I was looking around for some images of brown dwarf starts.  They are about 14 or so times the mass of Jupiter  (Jupiter is about 317x the mass of Earth, so these are about 4400 times the mass of the Earth) and are just perking away with a sustainable fusion reaction -- but barely.  One of the amazing things about nuclear fusion is that it can occur at relatively low temperatures and pressures (on a cosmic scale that is - still very very very high for us!)  - the solar core is about 15 million degrees C, or approximately hot to us.  The density is about 150 g/cm³  (lead is 11.3 grams per cubic cm, gold is 19.3 …  for figure about 10 times higher than the densest things we're used to).  It turns out fusion of the sort we see in the solar core proceeds very very slowly - a good thing as the Sun is about five billion years old and we need it to keep on ticking away.  The power density at the Sun's core - the rate at which energy is produced is about 275 watts per cubic meter …  You metabolize energy at the rate of about 1400 watts per cubic meter, so a volume of solar core your size would *not* give you enough energy to live, even if you were 100% efficient at absorbing it (and we are only in the tenths of a percent efficient at that!)  A lizard has a metabolism about 250 - 300 watts/m³.  This is why controlled nuclear fusion is *really* hard to do on Earth.  To get a reasonable rate - a higher power output - we need much hotter temperatures and higher pressures to encourage the hydrogen atoms to bump into each other a bit harder and a bit more frequently.  Temperatures at least ten times hotter than the Sun's core.  It turns out to be a pretty serious challenge.  

anyway back to brown dwarves ….

The surface temperature of a body determines what frequency of light it radiates.  Our skin temperature is about 35°C and we have a peak at about 9.5 microns.  The frequency range of the output is a micron or so wide, but the peak is pretty strong.  So if a camera is sensitive to wavelengths this long (red light is about 0.7 microns, blue is about 0.4), it can pick up your glowing self.  A problem is lots of other things are emitting at similar temperatures and it is difficult to image something as weak as a very dim star in the deep infrared.  Not to mention our atmosphere strongly absorbs these wavelengths.  The trick is a sensitive infrared camera on an orbiting telescope.  The Hubble has some cameras for this, but the Spitzer telescope goes down to 22 microns and does so with the ability to discriminate different wavelengths - so it responds to different IR "colors" .  We can see them visually by mapping them into colors in our band.  We get digital data back and assign different colors to different wavelengths.

The really dim brown dwarves aren't terribly inspiring, but are neat instances of very serious digital astronomy with enormous amounts of "data" being produced and analyzed (astronomers, physicists and astrophysicists have really helped pioneer the computational aspects of "big data" - ugh - I dislike that terminology!)

But while looking I came across a lovely composite image of MGC 7293 - the Helix nebula in Aquarius.  It is a planetary nebulae about 650 light years ago, so the light we're seeing left the nebula around the year 1560 AD - roughly the time period when Michelangelo died, Queen Elizabeth 1 was crowned and Galileo and Shakespeare were born.  It was a star that exploded as a nova and the expanding remnants of the explosion are illuminated by the white dwarf in the center (it is roughly earth sized, so very dense).  

A spacecraft called GALEX recorded a wavelength range from the ultraviolet to near infrared (0.15 to 2.3 microns)- straddling what we see, and the Spitzer does 3.4 to 4.5 and 8 to 24. Another spacecraft known as WISE does 3.4 to 4.5 microns.  

The white dwarf is a tiny white point at the center of the explosion.  It radiates strongly in the ultraviolet and this lights up the expanding wall of star stuff, which radiates in the infrared.  the color assignments are roughly red is cold, blue is hot…  A lot of the UV light is just reradiated as UV by some of the dust. Near the core there is a wide range of stuff going on - both hot and cold, so it looks purplish with these colors.

but enough of that … it also is very beautiful!  both in image and in the number of questions it gives -  both are really important

 

In the 70s Cargill made pre-satellite use of multispectral imagining.  It turns out that you can look at the reflected light from plants and tell their condition.  They had sophisticated film cameras operating at several wavelengths packed into a business jet that would overfly important crop fields in the Midwestern states.  By analyzing the results they often had a better understanding of crop conditions than the farmers and, more importantly, they had an understanding of the relative condition of crops before anyone else in the markets did.  Now days it is much cheaper to use satellite images

 

Isolating what your camera can record can give you an interesting feeling for your own world.  Simply pop on a filter than only transmits a narrow part of the spectrum and see what you get.  With digital cameras it is even easier - many image processing programs let you do this easily.  There are smartphone apps that do a good job - Hueless is a great little iPhone app that gives black and white images, but has several color filters built in.

 

The next step is to do photography in the near infrared and shortwave ultraviolet.  This gets a bit more complex with digital cameras as many have internal physical filters to prevent this, but it is possible and shortwave UV gives a sense of what many insects and even a few birds see, while IR is just plain fun.  Drop a note if you need any suggestions. 

 

We only have three color receptors that operate over a very narrow band, but even within that there are interesting variations.  The retinas in men and women appear to be similar, but there is a sexual dimorphism in spectral response that occurs in the brain.  Women are much more sensitive to fine gradations in red - something which came as a great relief to me as I'm poor at matching some colors and now I have an excuse.  In particularly they appear to be exquisitely sensitive to fine gradations of red in the skin - particularly in the face.  This correlates with the oxygenation level of the blood and can be an interesting signal  It is a really interesting out of band form of communication that we don't pay much attention to and women tend to be much better at it than men.  It is also something conventional color monitors currently can't handle.  Deeply curious research topics here!

 

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Recipe Corner

 

My grandma King was an expert baker even though her oven was terrible.  She never used standard measurements, which is unusal for a successful baker.  During her final year of life my sister and mother transcribed some of her mental recipes assigning measured values.  She was great with molasses and Fall is a wonderful time for ginger bread and ginger cookies.  So with that ...

 

 

Grandma King's Ginger Bread

 

 

Ingredients

 

° 2-1/4 c AP flour or cake flour (or a mixture)

 

° 1/3 c white can sugar

 

° 1 c dark molasses

 

° 3/4 c hot water

 

° 1/2c shortening

 

° 1 large egg

 

° 1 tsp baking soda

 

° 1 tsp ground ginger

 

° 1 tsp ground cinnamon

 

° 3/4 tsp unionized salt

Technique

° Heat oven to 325°F, grease and flour 9"x9x2 pan (metal).  Oven rack at mid level

 

° Measure all ingredients into a large mixer bowl and blend by hand or in a mixer on low speed for about 30 seconds -- don't over mix & constantly scrape the side of the bowl!

 

° Now beat harder for about 3 minutes (or medium speed) 

 

° pour  in pan and bake until a toothpick comes out clean - about 50 minutes.  Cool on a rack 

 

° serve with whipped cream

Grandma King's Ginger Snaps

Ingredients 

° 3/4c shortening

 

° 1/2 tsp non-iodized salt

 

° 1 c white cane sugar

 

° 1 large egg at room temperature

 

° 4 tbl molasses

 

° 2 c AP flour

 

° 2-1/2 tsp soda

 

° 1 tsp ground ginger

 

° 1 tsp ground cinnamon

 

° 1/2 tsp ground cloves

 

° white cane sugar for rolling

Technique

 

° Heat oven to 300°F, rack in middle and just above that if you are using two pans

 

° mix in order given and roll into walnut sized balls and then roll in a bowl of white sugar

 

° place on a sheet with 2" between and press flat with a glass bottom

 

° bake for 12 to 15 minutes until how you like them

 

These are very good with vanilla or chocolate ice cream between them.   You can roll them in a sheet and use a cookie cutter to make larger ice cream sandwiches

 

Comments

[Jean Russell]

I always love your twists - lines like " I'm poor at matching some colors and now I have an excuse."