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02/14/2020
Space Missions and Other Stuff
CHAPTER 111 Space Missions Revived and Retired
Am I now paying the price of the time spent in the sun in my youth with no sunscreen in a culture that promoted getting a tan if you were of the white persuasion? In December I went to my dermatologist for my 6-month full body checkup, returning in January to get the top of my head frozen with liquid nitrogen and to get biopsies on three growths. one on my nose and two on my left arm. The ones on the arm were squamous cell carcinomas while the one on my nose was a sebaceous cell carcinoma. Over my lifetime I've probably had at least 50 or so squamous and basal cell carcinomas but never had the sebaceous kind. My Googling of the term indicated the sebaceous one is a rare type of carcinoma, often occurring on the eyelid! Mine was at the top of my nose near my right eye. So, it was time for me to have my friendly Mohs surgeon go to work.
If you're not familiar with Mohs surgery, the surgeon first removes the visible cancerous material and a small amount of the surrounding area. The sample is then sectioned and mounted on slides and examined microscopically for cancer cells. If the sample area surrounding the cancer is free of cancer cells, that's it. The surgeon closes the wound (with stitches in my case) and you go home. That's what happened for the growths on my arm. It was a different story on my nose. Four slices were taken before the nose was free of cancer cells and I was there for over five hours! One reason for the lengthy process was that the surgeon found an unexpected basal cell carcinoma adjacent to the sebaceous one!
Enough of my surgeries. Let's turn to my favorite topic, space stuff. Two of NASA's space missions were in the news recently. One was Voyager 2 out there some 11 billion miles away beyond our solar system. Remarkably, it still communicates with us but last month, on January 25, it stopped communicating when it was programmed to perform a 360 degree roll. For some reason, there was too much power being drained and the spacecraft is programmed to shut down in such an event. Remarkably, its handlers back here on Earth were able to determine what was wrong and once again we can listen to Voyager 2 telling us about what's going on out there billions of miles away. As I've no doubt mentioned previously in these columns, the twin Voyager missions use plutonium to power the spacecraft. As the plutonium radioactively decays it gives off heat, which is converted to energy to provide the power. Of course, as the plutonium decays, there's less and less plutonium to decay and provide the heat so eventually there's little or no plutonium and hence no power and we will lose contact.
Just a few days later, on January 30, another space mission was officially pronounced at an end. That mission is the Spitzer Space Telescope, which was launched back in 2003 as one of NASA's four Great Observatories, which include the Hubble Space Telescope, the Chandra X-ray and the Compton Gamma Ray Observatories. In the Great Observatories program, NASA has used the four telescopes operating at different wavelengths to paint a comprehensive picture of our universe. The Hubble Space Telescope, operating in the visible range of the spectrum, is certainly the best known of the four and we've all seen many striking pictures of spectacular objects and panoramas in our universe. The distinguishing feature of the Spitzer Telescope is that it does not work in the visible part of the spectrum, but in the infrared region that is invisible to the human eye. The infrared region of the spectrum is also associated with heat (think the infrared lamp). Operating in the infrared, Spitzer has shown us things that other telescopes cannot. For example, take planet LHS 3844b, a planet outside our solar system orbiting a star known as an M dwarf, a very common and relatively cool kind of star in our galaxy.
LHS 3844b is about 49 light-years from Earth and is only about 30 percent larger than Earth in size. The remarkable thing is that Spitzer actually detected light coming from the surface of the planet, remarkable because normally the light from a star is so bright it overwhelms the light from one of its planets. However, this planet is probably in such an orbit that the same side always faces its "sun", like our moon has the same side facing us as it rotates around our Earth. The temperature of planet LHS 3844b is very hot, at least on the star-facing side, and being so hot means it's emitting infrared light, right up Spitzer's alley.
One of the most impressive of Spitzer's accomplishments was its contribution to the discovery of the planetary system TRAPPIST-1, seven planets of sizes close to that of Earth surrounding the star TRAPPIST-1A, almost 40 light-years from Earth. I devoted some space to this subject in my column of March 3, 2917. Most of the following is taken from that column. Three planets had been discovered orbiting TRAPPIST-1A by workers using the European Southern Observatory's Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. The planets were detected by noting dips in brightness of a star when a planet transits between the star and Earth. But about that time lead author of the study, Michael Gillon, noticed something strange about one of the transits and took a look at TRAPPIST-1 through ESO's Very Large Telescope in Chile and found not one, but three planets transiting at the same time! At this point, the Spitzer Space Telescope was brought into the study and seven planets emerged from all the various observations. During the 20 days spent on the Spitzer telescope, the researchers observed 34 transits. Needless to say, this planetary system will be the subject of study for years to come and the quest to find signs of chemistry compatible with life will be a major objective.
Most of the above paragraph is from my earlier column in 2017. Since then, TRAPPIST-1 has indeed been the subject of further investigations. Wikipedia has an excellent comprehensive article on TRAPPIST-1 covering just about everything you can think of- the conditions favorable and unfavorable to life, tidal locking (which leads to one side of a planet facing its star), possibilities of interactions that would break tidal locking, possible volcanic activities and other geologic situations resulting from the closeness of the planets to each other, possible melting of ice on an otherwise unsuitable-for-life planet due to such interactions, very heavy amounts of radiation from being so close to the star, etc. While no signs of life have been seen on any planet anywhere, TRAPPIST=1 is still in the running. All in all, I'm left with a feeling of amazement at how lucky we humans are to have evolved on a planet that has had all the conditions and history (notably the asteroid that killed the dinosaurs) that have allowed us to exist and thrive.
Part of that history is the formation of the planets in our solar system I'm writing this paragraph on Valentine's Day and in today's Star-Ledger there's a brief item about an article published in the February 14 issue of Science on the "city-sized" object photographed by NASA's New Horizons spacecraft over a year ago. You will remember it as an object that looked like a snowman with a reddish tint and it is located way out in space beyond Pluto. The object now has an official name, Arrokoth, a Native American term meaning "sky". The data from the New Horizons mission to Arrokoth have been analyzed and the researchers are apparently proposing that the formation of planets may not have been as violent a process as previously proposed. Arrokoth is composed of two more or less spherical objects which have fused together in a relatively gentle manner, as if they might have been orbiting each other and fused together without any significant breakup or destruction. Arrokoth is a relic of the days of planet formation that has remained untouched for billions of years. Meanwhile, the New Horizons spacecraft continues to travel out there in the Kuiper Belt and one can hope it might find other undisturbed objects to fly by and capture images of them.
Finally, in that column in 2017, I mentioned getting an email from the daughter of Harry White, a fellow I knew and worked with at Bell Labs. In that column I mentioned how much I enjoyed working with Harry on light emitting diodes and how I called him in California and we chatted about the good old days at Bell Labs. Sadly, just a few weeks ago, I got another call from his daughter telling me that Harry had passed away. We had a long conversation and she told me that Harry often commented about how much he enjoyed working with me on LEDs and I told her that those years were the happiest for me in my 37 years at Bell Labs.
Allen F. Bortrum
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