Secret Science Club Lecture Recap: Astrophysics Endterm Exam

Last night, I headed down to the beautiful Bell House, in the Gowanus section of Brooklyn, for this month's Secret Science Club lecture, which featured the triumphant return (I have to confess that my lecture recaps became much more serious when I started taking notes- the SSC really forced me to become a better, more responsible writer) of astrophysicist Dr Charles Liu of The City University of New York College of Staten Island and the Hayden Planetarium and Department of Astrophysics of the American Museum of Natural History.

Dr Liu began his lecture by joking about whether he describes himself as an astronomer or an astrophysicist- if he's sitting on a plane next to someone he wants to talk to, he describes himself as an astronomer... if he doesn't want to talk to them, he describes himself as an astrophysicist. He noted that yesterday was the last day of finals at school, so he wanted to give us a 'holiday sampler', starting with the astrophysical significance of the Winter Solstice- simply the day on which Earth's northern hemisphere receives the least amount of sunlight, but not necessarily the day on which the sunrise was latest or the sunset the earliest. He noted that the increasing darkness before the solstice tended to worry many ancient peoples, so they created special commemorations of the day, such as Saturnalia, which involved societal role reversals, gambling, and merrymaking (Dr Liu likened it to Mardi Gras). Most of the winter solstice holidays in the northern hemisphere involve the use of artificial lights amid the darkness of the solstice. Dr Liu quipped that these holidays are all due to astronomy.

Dr Liu then showed one of those gorgeous photos of Pluto and noted that he did not vote for the demotion of the dwarf planet. He noted that the New Horizon probe's closest flyby of Pluto occurred in 2015, but that the data from the probe has still been coming in throughout 2016, and the final data dump will soon occur. Pluto has a highly elliptical orbit and is currently moving farther away from the sun. Pluto is getting colder, and its atmosphere is precipitating to the surface. Pluto has a varied geology. Earth's geology is largely driven by the heat from the planet's interior, while Pluto's may be largely driven by the cold- Pluto's atmosphere has distinct layers of haze which form as atmospheric gases freeze into ice crystals. Dr Liu joked that Pluto is cool in the hot sense as well as in the cold sense, and noted that Pluto is cool no matter what its designation is, and he exhorted us to enjoy the beautiful new discoveries.

Dr Liu then gave us an overview of LIGO, the Laser Interferometer Gravitational-Wave Observatory. Spacetime 'ripples' much like the surface of a pond- the fluctuations in spacetime were predicted by Einstein when he formulated his theory of general relativity. LIGO uses two antennae arrays, one in Washington state and one is Louisiana, to detect fluctuations. LIGO operated for ten years without any 'action', at the cost of hundreds of millions of dollars. After ten years, additional funding was approved, and the antenna arrays were improved and gravitational waves were detected in 2015. The two detectors received the results about 1/1000th of a second apart, a ripple of spacetime with the dimension of an entire planet created a distortion the width of an atomic nucleus. The LIGO team is favored to win the Nobel Prize in Physics- a whole area of physics, gravitational waves, has now been solved. The source of the gravitational waves detected by LIGO was a set of two colliding black holes which are circling each other wan will collapse/combine into one black hole. Dr Liu tasked us with imagining the immense amount of power which will be released in this collapse as mass is converted into energy- a mass one three-thousandth of Earth would produce more energy than that our sun would produce in a billion years. Dr Liu joked that astronomers are cool, because they get to hang out, contemplating explosions powerful enough to destroy entire solar systems.

Dr Liu then mentioned the upcoming James Webb Space Telescope project. He noted that the Hubble Space Telescope is twenty-seven years old, and that it was recently saved due to public outcry- with the telescope's gyroscopes being serviced weeks before they would have failed, providing seven more years of perfect performance, though Dr Liu warned us that the Hubble could go at any time. The James Webb Space Telescope is designed to have different capabilities than the Hubble- it will be situated in a solar orbit at the L2 Lagrange Point. The James Webb Space Telescope will be able to operate twenty-four hours a day, seven days a week, and will have an umbrella-like sunshield. The JWST will be able to observe light in the infrared, visible, and ultraviolet wavelengths. Dr Liu gave the audience some career advice- the Panoply of Space Telescope Awesomeness will require staffing, so brush up on your resumes.

Dr Liu went on to discuss the upcoming Daniel K. Inouye Solar Telescope project, named in honor of the late senator from Hawaii. The DKIST, located on Maui, is scheduled to begin operations in 2019 and is designed to observe the sun in the ultraviolet and infrared spectra, using solar-adaptive optics. It is designed to observe solar spicules. Dr Liu joked that the DKIST project is also hiring, and gleefully noted that the is a really exciting time in the field of astronomy.

Dr Liu then opened up a question and answer period, which he jokingly referred to as his own 'final exam' for the semester. He had audience members write questions on pieces of paper which were then passed up to him. Some bastard in the audience asked him to sing his black hole song from his previous lecture. The first question concerned the number of black holes in the universe, which Dr Liu said was increasing. Someone else asked if we could be wrong about gravity- Dr Liu said maybe, but gravity is a fundamental force of the universe, so no matter whether one adheres to string theory or a holographic model of the universe, our understanding of gravity is not disproven. In order to change the fundamentals of science, one has to show that everything is wrong, as Einstein showed that Newton was wrong because he didn't see enough of the universe. Dr Liu told us not to worry about these sort of things.

The next question dealt with climate change- Dr Liu indicated that climate always changes, but that natural changes occur over thousands of years. Humans have been altering the climate at an accelerated pace. Dr Liu noted that we had to worry about the short-term problems caused by climate change, but warned against grandiose geoengineering projects which could have long-ranging consequences. He noted that our main focus should be on carbon sequestration and helping poor people to survive natural disasters due to climate change. He said that we should solve the problem using the things we know rather than going off into unknown territory with geoengineering.

Dr Liu also noted that all science is important- using the example of climate science, he reminded the audience that oceanic science, earth science, and space science all contributed important knowledge to our understanding of global warming. Our understanding of the greenhouse effect was derived from studying Venus and Mars. All fields of study are parts of one whole- science is not a zero sum game and all scientists should work together. He also noted that scientists needed to be lobbyists in order to secure funding for research.

The next question regarded terraforming Mars- Dr Liu was of the opinion that it would take at least one thousand years to make Mars as liveable as Earth. Regarding his favorite molecule, Dr Liu joked that it was the beer molecule.

Another question regarded black holes- is there something on the other side of a black hole, such as a white geyser or a budding new universe? Dr Liu noted that there is no evidence for this sort of thing, and told us to think of a black hole as a sort of cosmic 'hernia'- the matter absorbed by a black hole kinda just 'hangs off of' the universe. While Stephen Hawking predicted that Hawking radiation would be released from black holes, there is no evidence of any white geysers, and there is no evidence for any other 'big bangs' than the original one.

When asked about SpaceX and the dream of colonizing Mars, Dr Liu noted that Elon Musk is a great salesman, then he exhorted us, 'Think big, and don't bet against humanity.'

Asked about how space junk is cleaned up, Dr Liu joked that there are no garbagemen in space, but noted that orbits decay, debris re-enters the atmosphere, and burns up. Asked about navigating through an asteroid field, Dr Liu noted that the average distance between asteroids is one million miles- sorry, Han Solo, no hotshot piloting is needed. Another questioner asked how the James Webb Space Telescope would be maintained, and Dr Liu noted that it wouldn't be- it works or it doesn't. He then went into a tangent about the Large Synoptic Survey Telescope under construction in Chile... it will have an array of 320 megapixel cameras to photograph the entire sky every night for ten years in order to build up a database of celestial objects- he noted that LSST will operate from 2023 to 2033 and asked if any of us were considering a career change.

Asked about the coolest thing about astronomy, Dr Liu joked, it puts a roof over my head and feeds my family. He then told us that, no matter how bad a day he's had, he's certain that the Earth won't be destroyed in the next five billion years. He said that what matters is today, and that although he's seen bad things, to think about the good things. He gave a passionate soliloquy- we live in a place, not just Brooklyn, where we can disagree without killing each other, without hating each other, we can even love each other. Be vigilant, be careful, speak up, but we will be fine in the end. Today will change the course of the future, but look to the stars... when things are crazy down here, look up. He then quoted from Robert Frost's poem Choose Something Like a Star:


O Star (the fairest one in sight),
We grant your loftiness the right
To some obscurity of cloud—
It will not do to say of night,
Since dark is what brings out your light.
Some mystery becomes the proud.
But to be wholly taciturn
In your reserve is not allowed.
Say something to us we can learn
By heart and when alone repeat.
Say something! And it says, 'I burn.'
But say with what degree of heat.
Talk Fahrenheit, talk Centigrade.
Use language we can comprehend.
Tell us what elements you blend.
It gives us strangely little aid,
But does tell something in the end.
And steadfast as Keats' Eremite,
Not even stooping from its sphere,
It asks a little of us here.
It asks of us a certain height,
So when at times the mob is swayed
To carry praise or blame too far,
We may choose something like a star
To stay our minds on and be staid.


After the written Q&A session, Dr Liu continued with an oral Q&A. Some bastard in the audience asked him to consider CERN with an astronomer's eye- what would be his dream discovery from Switzerland? Dr Liu stated that it would be the discovery of a graviton. While one can infer the existence of a graviton, such a particle would be one-billionth the mass of the lightest particle known. In order to discover one, a particle accelerator would have to increase in size and power, and the odds of a particle accelerator the size of Europe being built are slim.

Asked about dark matter, Dr Liu noted that it is observed through its gravitational effects, and that for every pound of baryonic matter in the universe, there are four or five pounds of dark matter. Dr Liu compared dark matter to the headlights of a vehicle- we can see the headlights and infer the mass of a car behind them.

Asked about the multiverse, Dr Liu noted that it could exist, but there would be a zero-percent chance that we could visit it using any current knowledge. He then quipped, 'Our universe is plenty big.' When asked how far back in time we can look, he noted that the cosmic horizon equals the age of the universe (13.8 billion years) times the speed of light. Looking out is looking back in time- it takes eight minutes for the light of the sun to reach the Earth, so we see the sun as it was eight minutes ago.

Asked about the possibility of faster-than-light travel, Dr Liu said that we would have to think beyond the four-dimensional universe and noted that Mexican physicist Miguel Alcubierre speculated the use of a bubble outside of spacetime which would allow apparent FTL travel.

Asked about the role of the public in funding science, Dr Liu characterized scientific societies as 'the tail that wags the dog' and joked that people loved the Hubble Space Telescope because the beautiful images it produced ended up as their screen savers. When asked about which Star Trek series he loved best, Dr Liu cried, it's like choosing between his children, then noted that, while TNG had the best episodes, it wasn't the best series, and that Voyager had its charms.

The last question concerned energy in the expanding universe- as the universe expands, the energy goes up. There is an inherent amount of energy in each cubic inch of space, and there is something counteracting gravity- the universe is accelerating in its expansion. As the energy increases, the amount of matter stays the same- we don't know where this energy comes from. As cosmologically abhorrent as the cosmological constant appears to be, it's what the universe tells us must be. Dr Liu then noted that a Dark Energy Survey is underway... I think I'm going to update my resume.

Once again, the Secret Science Club dished out a fantastic lecture, a sort of 'Astrophysics Greatest Hits of 2016' survey, or a 'State of Space Science Survey'. Dr Liu is a passionate, humorous advocate for astrophysics and, yes, he did sing the black hole song to the tune of Day-O, with audience participation, of course. Kudos to Dr Liu, Margaret and Dorian, and the staff of the beautiful Bell House.

Here's a great video of Dr Liu doing what he does best- advocating for science with passion, wit, and charm:





I'd say that the good doctor passed his end-of-semester final exam with flying colors... in a range from the infrared to the ultraviolet.