One satisfaction of astronomy is the sense of continuity with astronomers from all over the world and spanning the decades, centuries, and millennia. The wonders of the sky fill us with awe and provoke so many questions. I appreciate the multidisciplinary approach to answering these questions.
Today’s anecdote concerns an article published this week, with 25 authors from 5 countries. The Chinese Chang’e 5 probe brought back to Earth the first lunar samples in 4 decades. They targeted a place on the Moon that was suspected of being young, due to the region’s low density of craters. Galileo observed craters on the moon 400 years ago, but it was only in the 1960s that meteor impacts were confirmed to be the dominant mechanism of their origin.
The observational and theoretical development of celestial mechanics, universal gravitation, the solar nebula, and planetary accretion were all required to understand dating planetary surfaces, by measuring the size and number of craters. We also needed telescopes, rockets, robotics, petrology, geochemistry, and geochronology to complement the study. The Moon is the only planetary body where impact crater ages have been calibrated with radiometric dating, but there had been no samples so far measured that are between 3.2 and 0.8 billion years old. The new samples were dated at 1.96±.06 billion years, sitting in the middle of that gap and forcing a revision of the current crater dating method. The new date is very young for the Moon’s surface and brings up new questions, like why the Moon was still melting crust so recently.
I’m filled with a sense of connection with my fellow humans who can conceive of such questions, work on them from many different aspects over the centuries, answer some, and end up with even more questions. And I look up at the sky with happiness.
Dr. Michelle Kunimoto is a postdoctoral associate working on NASA’s Transiting Exoplanet Survey Satellite (TESS)mission. She leads the Quick Look Pipeline team at MIT which is dedicated to analyzing TESS data to discover and characterize exoplanets. As an undergraduate, her discoveries of four planet candidates landed her on the Forbes 30 Under 30 list in 2017. Michelle is BC born and raised and received both her undergraduate degree and her PhD at the University of British Columbia.
Finding Earth 2.0 – Dr. Michelle Kunimoto
Michelle spoke about how we find exoplanets, identify potentially “habitable” planets, about what she does as a researcher with NASA’s TESS mission, and how anyone can join the hunt for new planets.
Are we alone? What would other life look like?
Assuming Earth-like conditions for life
Small, rocky, watery planet with an atmosphere
In the habitable zone around a host star
Stars that are similar to our Sun – “just right” and stable, long-lived
30 years ago, the first exoplanets were discovered by Alex Wolszczan and Dale Frail
Gordon Walker actually discovered an exoplanet back in 1988 from Victoria, but not confirmed until 2002
How to detect an exoplanet
Doppler shift due to Stellar Wobble – radial velocity
Transit – the method Michelle uses in her work
Kepler – NASA’s first exoplanet discovery mission
Used the transit method from 2009 to 2013
150,000+ stars observed for 4 years
Revolutionized exoplanet by discovering over half of all dis
K2 mission extended the discoveries to 2018
Tess – NASA mission started in 2018
Full sky coverage
Orbits around the Earth in a following, elliptical orbit
27 days to a full year of observations for each object
Automated detection, then manual verification to avoid false positives
Michelle has discovered 1,600 candidate planets
Whole mission has confirmed 152 out of 3,285 candidate planets
A total of 4,531 exoplanets have been discovered (not just from the Tess mission)
Diversity of exoplanets is extensive
3 in habitable zone, and Earth-sized
James Web space telescope will examine this system in detail
20 candidate exoplanets have been discovered that are Earth-sized and appear to possibly support life as we know it
Keppler-452b – most Earth-like exoplanet
Transmission spectroscopy – detect the characteristics of an exoplanet’s atmosphere
Carolyn Shoemaker died last month. After her children had grown up and she was 51 years old, she started her astronomy career. She helped establish the Palomar Asteroid and Comet Survey, and for decades she studied the photographic plates coming off of the 18 inch Schmidt wide-field telescope, located in a dome next to the Palomar 200 inch telescope. At an average of 1 discovery for every 100 hours spent at the stereoscopic microscope, she became the world’s top comet finder.
This was more than a job. Everybody who knew her emphasizes her enthusiasm and humour. Among these friends is an acquaintance of several of our centre members, David Levy. On March 23, 1993, David passed some photographs he had just taken of the region near Jupiter, and Carolyn exclaimed that she saw in these images a strange “squashed” comet. This comet became known as Shoemaker-Levy-9. It was actually the 11th comet they had discovered together, but two were aperiodic and so had a different naming convention. I remember the excitement, when 4 months later, 21 fragments of SL9 crashed into Jupiter with images from professionals and amateurs alike started pouring in. We got to watch a cosmic collision in real time!
What kept Carolyn Shoemaker at this slow, painstaking task was similar to what many amateur astronomers feel. She said “The thrill of discovery is deeply satisfying”. Few of us will get the opportunity to do cutting edge science with the best instruments available, but all of us get our own personal thrills. Whether the discovery is at the eyepiece, or on the computer monitor, or from a revelation that comes during a talk at our Astro Cafe, the experience continues to be deeply satisfying. In memory of Carolyn Shoemaker, I wish you all many more of these deeply satisfying moments!
Photos of the Moon taken through a Dobsonian telescope with 25mm, 7.4mm and 10mm eyepieces
Some optical illusion showing a bear shape on the Lunar surface
Next Monday is Labour Day, so no Astro Cafe
Current health orders preclude us from restarting in-person meetings. We had planned to restart Astronomy Cafe for mid-September at the Fairfield site, but Victoria Centre has rented the space, so we will keep members posted when the situation improves.
I’ve had a couple of requests this summer to help friends who have never seen Saturn through a telescope with their own eyes before. One of them was lent the wonderful 1970s Tasco 60mm refractor that I bought off Reg Dunkley, at our Astro Cafe exchange, way back when we could meet in person. Reg says this telescope kindled his interest in astronomy years ago, so it is fun to give this equipment to another enthusiastic newbie. The other request is from Toronto and I’m getting a RASC Toronto Centre loaner scope ready, for when I’m there next week. We do indeed belong to a great society that gives us these opportunities.
But what is it about seeing the beautiful objects in the sky ourselves? There are much better images available on the internet. Nothing we can see from Earth compares to the pictures of our sixth planet sent by the Voyager and Cassini spacecraft. Saturn especially has been something that has turned on people from all walks of life to the delights of the night sky. Indeed, the design specifications for the “Galileo-scope” included the possibility to see the rings of Saturn, because they knew that that view is the gateway to spending more time with a telescope (I have one, and it works!).
Saturn is certainly other- worldly. It is beautiful in its form and symmetry. The physics which produce the rings are non-intuitive. It is a challenge to see it, but not an unreasonable challenge for most. But there must be more.
Each time I take my telescope out, I fall in love again with the universe we live in. Even when I am alone, I sometimes swoon out loud. I don’t know why, but I sure am glad I get to share the feeling with my astro-friends. As our friend Diane Bell told us: “the sky is a gift!”
Enjoy the sky. Share it. Look Up, Randy Enkin, President email