Indulging in some fine ice cream I found myself thinking about my Grandpa Joe. Good ice cream was an art-form to him and he exposed me to good homemade examples early on. These days I rarely have it and usually make my own, but every now and again a very high quality ice cream is called for - in this case Jeni's Splendid Salty Caramel. I only had a little as it is spendy and laced with saturated fat, but as I thought about him I looked at the nutrition label and did a quick mental comparison with something else I associate with him - dynamite.
It seems he was rather good at it. Harsh economic times caused them to lose their property to the East of Park City, Utah and he was forced to work a variety of odd jobs to support the family. Economies were observed and he decided a cheap and efficient way to provide protein was to fish with dynamite rather than a hook. A stick or two could produce a few week's protein which could be traded with other families.
About a megajoule of energy is stored in a standard stick of dynamite.1 I was having about four ounces of caramel ice cream - 260 nutritional calories by the label or just under 1.1 megajoules. The different is power - the rate by which energy is released. Energy from the Jeni's is released over a period of hours while the dynamites is released in about a thousandth of a second.
He told me stories about some strange things that were liberated from the lake during his fishing trips. It had a secondary use of probing lake and river beds. Explosions have a nice way turning things inside out...
We're seeing some of that right now in the Northern sky. One usually thinks of discovery in astronomy taking place on remote mountain tops or in space with enormous telescopes, but most professional telescopes have very narrow fields of view to study very faint objects. This one involves a 14 inch teaching telescope at the University of London's Observatory - not exactly primo territory for a dark night sky.2 And the weather was closing in, but the telescope was pointed at a standard target well-known by all amateur astronomers in the Northern Hemisphere.. M82.
“The weather was closing in, with increasing cloud,” Fossey says, “so instead of the planned practical astronomy class, I gave the students an introductory demonstration of how to use the CCD camera on one of the observatory’s automated 0.35–meter telescopes.”
The students chose M 82, a bright and photogenic galaxy as their target, as it was in one of the shrinking patches of clear sky. While adjusting the telescope’s position, Fossey noticed a ‘star’ overlaid on the galaxy which he did not recognize from previous observations.
They inspected online archive images of the galaxy, and it became apparent that there was indeed a new star-like object in M 82. With clouds closing in, there was hardly time to check: so they switched to taking a rapid series of 1 and 2 minute exposures through different coloured filters to check that the object persisted, and to be able to measure its brightness and colour.
Meanwhile, they started up a second telescope to obtain a second source of data, to ensure the object was not an instrumental artifact. By about 19:40 GMT, the cloud cover was almost complete, but it was just possible to make out the new object in the second data set: this was a real astronomical source.
Guy Pollack: “It was a surreal and exciting experience taking images of the unidentified object as Steve ran around the observatory verifying the result. I’m very chuffed to have helped in the discovery of the M 82 Supernova.“
Tom Wright: “One minute we’re eating pizza then five minutes later we’ve helped to discover a supernova. I couldn’t believe it. It reminds me why I got interested in astronomy in the first place.”
Stars constantly change over their lifetimes with the beginnings and ends often packing some drama. Our existence depends on various forms of this drama as most of the observable matter produced during the first three minutes after the Big Bang consists of hydrogen, helium and a bit of lithium. The universe undergoing rapid expansion and the process of making new atomic nuclei from protons and neutrons stopped around twenty minutes out with tiny bits of beryllium being formed. A nice start. Enough to allow stars to form, but the building blocks for life weren't there.
Stars, of course, did form and as they aged new elements were formed. As it happens their initial mass predicts much of their future. Most stars, including the Sun, will end up as white dwarfs. A variety of elements, all lighter than iron, can be formed but many necessary for life are skipped. Many of these, including our Sun, will end up producing a lot of carbon, nitrogen and oxygen. There will be massive energy bursts that eject large amounts of mass into an expanding shell. These shells are planetary nebulae and, illuminated by the now smaller remnant star.3 In end a good deal of the Sun and all of the planets surrounding it will form a very beautiful object. The ejected shells keep expanding and are used to help create new stars and their solar systems - recycling at an enormous scale!
Fortunately for life there are other ways to create elements in a star and move them into space. Supernovae are extremely violent stellar explosions. There are several types but since the discovery in London was a Type 1A Supernova, we'll focus that kind.4
Stars often form in binary pairs - orbiting around a common center of mass. Imagine a pair that are evolving at somewhat different rates where one has become a white dwarf. The other can be one of a variety, but imagine it being like our Sun will be just before it collapses and forms a white dwarf - a red giant.5 Some of the atmosphere from the red giant is caught by the gravity of the white dwarf which gains mass by accretion.
The white dwarf slowly grows until it gets to about 1.4 times the mass of our Sun. Then things get really interesting.6 The core temperature rises to a level where carbon fusion can take place, but the star is unable cool itself normally. It simmers along for perhaps a thousand years and then a conflagration flame starts internally and quickly spreads through the star with the internal temperature rising to billions of degrees. There is enough temperature and pressure for a lot of elements to form and a violent explosion occurs releasing about 1 to 2 *1044 Joules of energy. Big numbers are difficult to get a handle on, but think of the energy the Sun releases in its lifetime -- this is on that scale and it is released in seconds. A bright flash is produced, often as bright as a galaxy and what was left of the star moves away at about five percent the speed of light.
The flash has some interesting characteristics. One is its brightness - about five billion times as bright as the Sun. The mechanism for producing it is the same in all Type 1A supernovae as the triggering mass is the same, so the brightness or luminosity is about the same.
Astronomers love these events. If you have similar flashbulbs going off and you use the inverse square law and estimate their distance to reasonable accuracy. They become standard candles that allow you to measure the distance to galaxies.
Here is a video of one set of calculations from a massive simulation of about the first second of one of these events. It is sobering when you consider that one of these 25 light years from Earth would certainly wipe out all life here.
But they complete the set of all the building blocks we have and move them into position where new solar systems can form. Much of the matter we are made of are the result of not one but several - perhaps a dozen or so - "nearby" supernovae billions of years ago. We are literally stardust.
So go out and look up at the Big Dipper and think about this event that is laying the ground for the creation of new solar systems and perhaps new life.7
1 One of those nice little factoids one tends to remember. A standard stick in the US is 8 by 1.25 inches and weighs about 0.2 kg. The energy density for standard dynamite is a disappointing 5 MJ/kg. Two hundred and fifty nutritional calories is about a megajoule - so the average daily diet of 2,000 calories packs the energy equivalent of eight sticks of dynamite.
2 14" is small for a professional telescope, but is a common size for advanced amateurs and for hands-on astronomy and astrophysics courses. You can also do serious work with such instruments. For scale one like this on a good mount is probably in the $25k range. More sophisticated optics, electronics and automation can easily take you over $75k, but there are people who put far more than that into boats.
M82 and telescope images courtesy University College London
3 The term planetary nebula is historic and the result of bad optics and an insufficient understanding of astronomy. William Herschel thought they were newly forming planetary systems. Nebula is Latin for mist or cloud and these were blurry blobs in his telescope. The name stuck, but doesn't make much sense. Such is science.
4 This is really exciting stuff, but there is no room or time for a reasonable discussion. Ping me if you want to go deeper and I can recommend books depending on your background.
5 At some point our Sun in about four billion years will have exhausted most of its hydrogen and the core will shrink and heat up. The part of the Sun outside the core will expand - probably past the Earth's orbit. The surface temperature will be cooler causing it to appear red. It will still have the same mass, but its volume will be about ten million times greater so the density will be very low by our standards.
6 1.4 solar masses is a very interesting point in astrophysics. It also is close to the Chandrasekhar Limit. In his early 20s Subrahmanyan Chandrasekhar worked out the relativistic quantum mechanics that said stars with greater masses would have enough internal gravity to crush protons and electrons into neutrons allowing the star to collapse into a tiny neutron star - a star with a diameter on the order of ten miles.
7 look around for star maps to pinpoint M82
A nice healthy soup for a cold day. It was thrown together so these are guess measurements, but it should make a good start. More water if you like thin soups, less if you like them thick. It would be nice served with a good bread and perhaps some sour cream and thin slices of avocado as a garnish. If it was the summer with great tomatoes (sigh) I would dice a couple and stir them in prior to serving.
Red and Green Pepper Soup
° 1 tbl olive oil
° 1 large red bell pepper
° 1 large green bell pepper
° 2 red onions
° 4 garlic cloves, diced
° 2 tsp cumin
° 1 tsp dry oregano
° 1 tsp cayenne
° 1 tsp coriander
° 1/2 tsp cayenne pepper (more if you like it hot .. I used about a full tsp)
° 1 tsp sea salt
° 1 28 oz can kidney beans, rinsed
° 3 cups water
° thinly slice the bell peppers and onions and start the oil warming in a large pan over medium high heat
° add the vegetables and cook until the pepper skin blistered and starts to caramelize - maybe five minutes. About a minute before the next step ad the garlic.
° push the vegetables to one side of the pan and add the spices to the bare side. Toast for about a half minute and then mix and coat the veggies. Throw in some of the water to de-glaze the pan and scrape the yummy brown residue from the bottom and mix it in.
° add the beans, salt and what's left of the water and bring to a boil. Reduce the heat and simmer for about 20 minutes.