On August 25, 1989, I was in the observatory at Villanova University taking data with the astronomy department’s 15-inch telescope. The telescope was doing it’s thing – measuring the shift in brightness of a binary star system as one star eclipsed its companion hundreds of light-years away. It wasn’t exceptionally difficult work – you boot up the computer, point the telescope to its target, turn on the photometer and let the photons come trickling in. In a roll-off roof observatory, I had the entire night sky to gaze upon, which I typically did during those long observations.
But on this night, my attention was turned toward a television set I brought into the observatory. I turned the brightness almost all the way down, and tuned to WHYY, the local PBS station serving the greater Philadelphia area. I never watched TV while observing before, but tonight Voyager 2 was making its closest approach to Neptune, and I was going to see it live.
The broadcast was billed as “Neptune All Night” – a live, real-time telecast as Voyager 2 made it’s closest approach 5,000 miles above Neptune’s cloud tops. From midnight until 7am, I watched image after raw, grainy image appear on the screen revealing an alien world as seen by the spacecraft as it flew by at 42,000 miles per hour.
During the broadcast, a panel of astronomers from the Franklin Institute, the University of Pennsylvania, and even a science fiction writer commented on the images as they were coming in.
Clearly, there were millions of people watching. I’m sure there were watch parties in people’s homes, universities, and of course at JPL, where the mission was being run and was the primary broadcast center for the evening’s flyby. Throughout the evening, people would call in asking questions the experts did their best to answer.
But standing there, alone in the dark, it felt at times that it was just Neptune, Voyager, and myself. I often looked up from the TV toward the southwest sky, where, 2.7 billion miles from earth, our robotic emissary was transmitting these images.
As Neptune set in the southwest, the encounter was coming to an end. Toward the east, the sky was lightening and the Sun would be up soon. I ended the observation, closed up the telescope, shut down the computers, and closed the roof.
My friend Mark “Indy” Kochte has done it again, producing a spellbinding time-lapse video of the night skies. Turn up the sound, click HD, go fullscreen, and behold:
As the title of the video suggests, the sequences were shot in Joshua Tree National Park during two separate weekend visits to the Park, one in September, one in November (during the 2012 Leonid Meteor Shower). Quoting Mark’s writeup, here are some cool bits in the video:
The bright star-like object that appears from behind a sky-silhouetted Joshua Tree at 0:15 is Jupiter. Jupiter also appears at 0:24, 0:38, and rises through the Arch near White Tanks Campground at 0:57.
The shadows that play across the rocks in the Arch sequence are from the moon setting behind the camera.
Venus makes an appearance at 0:50 and rises during the final sequence at 1:38
The star trails at 1:13 were created using StarStax. On the left side of the field of view at 1:19 you’ll note the appearance of a bright shaft of light. That was a minor fireball from the Leonid meteor shower. All the other streaks you see shoot across the field of view are planes.
The final sequence (at 1:28) features a classic instance of Zodiacal Light, the glow you see in the sky as the camera pans from right to left. It was *very* evident with the naked eye. It took me a while to figure out that it wasn’t light pollution from a distant town (of which there are no light domes in that direction from Joshua Tree), but rather an extremely vivid case of Zodiacal Light. (I have only seen it this bright once since during a trip to New Mexico in 2013)
The lights on the hill from 0:33 to 0:38 are of some night hikers a few miles away from where I was shooting.
Now I got to get to Joshua Tree Park and see this for myself, in real time of course.
I’ve been meaning to write about my experience at this year’s Launch Pad Astronomy Workshop for a while now. Ok, who am I kidding, I’ve been meaning to write about anything on this blog for a while now but I’ve been so busy with my new job that there has been precious little time for anything else. (In fact, no sooner did I return home from Wyoming than I had to re-pack my stuff and head up to New York City for meetings — talk about contrast.)
Which is why Launch Pad couldn’t have come at a better time for me. Yes, it’s a lot of work, and yes, it consumes a great deal of my personal CPU, but it’s a welcome reset from the daily routine and a chance to do what I love to do best — tell cool people about the universe.
And what a bunch of cool people! Launch Pad self-selects for those who want to learn astronomy and who are willing to commit the time and expense to spend a week with us in Laramie, WY to do it. Each year brings a group of truly wonderful people and I couldn’t have been more delighted to get to know this years’ participants.
Far better writers than I such as Andrew Liptak, Jenn Reese, Sarah McCarry, Susan Forest, Gabrielle Harbowy, and others took the time to express their thoughts on this year’s Launch Pad and I highly recommend checking them out. In the meantime, as promised, here are my slides from this year’s workshop (NOTE: The file sizes on most of these are very large so please be patient as they download):
Exploring Our Solar System — I’d like to think this subject is somewhat self-explanatory, but it’s awfully hard to condense the entire solar system into a one-hour talk. Especially since we’re finding out so many things about it. Motion, Energy, and Gravity — I had to rush through this one to get it ready for presentation but I think we got the main points covered here. Binary Stars and Exoplanets — I pride myself on this one as the work I did on binary stars as an undergrad used the same techniques that detect extrasolar planets today. It turns out it wasn’t a matter of telescope power — the signal was hiding in the noise the whole time, just waiting for the computational horsepower to improve. Stars — How stars’ temperature and radii determine their luminosity, how their spectra allow us to classify them according to their temperature and mass, and how they form in the first place. Stellar End States, Part 1 — How low-mass stars evolve and die, with a preview of things to happen to our Sun starting in a few billion years. Stellar End States, Part 2 — Ok, I admit it, I just couldn’t top Mike Brotherton’s awesome slides so I used them instead. Either that or I ran out of time and had to resort to Plan Z.
Getting to share the universe with such wonderful people is always a joy, but I think this year was extra special thanks to our advisor Peepy dropping by to help us.
In this week’s astronomy lab, my students needed to make some simple calculations, mostly involving some arithmetic and a little bit of algebra to convert hours and minutes into decimal hours (for example, 1hr 30min = 1.5 hrs) and some arithmetic. Nothing too complex, but it was nevertheless a major challenge for many of my students, eliciting groans of “I suck at math”, “I’m not a math person”, etc.
I’m sympathetic, to a point. I struggled with math quite a bit as a wee lad, and even as an undergraduate astronomy major in college (don’t tell anyone). But looking back, I realize that the reason I “sucked” at math was because I told myself I sucked at math. Once I decided I no longer sucked at math, I suddenly got better at it.
I watched this happen to a student when faced with the problem of calculating the difference in time. He was struggling with some time calculations and asked me for help. It went something like this (and yes, I’m paraphrasing):
Me: Ok, so you need to figure out the time difference between 1:16 and 1:21. What is it? Student (tired, frustrated): Oh man, I’m just not sure right now. Me: No problem. Let’s imagine you and I are playing blackjack together in Atlantic City— Student: Now you’re talking my language! Me: Cool. So you’re dealt a 7 and a 9. What do you have? Student: 16, a really sucky hand. Me: And the dealer is showing an 8, what do you need to do? Student: This sucks, I have to hit. Me: Yeah, you do, but what do you have to pull in order to make 21 and guarantee you won’t get beat? Student: A 5. Me: Right, so what’s the difference between 1:16 and 1:21 again? Student: Oh geez, of course. Duh!
I got a little lucky here – I didn’t know that the student played blackjack, I just guessed. But mathematically, the problem was the same. The context of the problem seemed to make all the difference. At the blackjack table, he no longer seemed to think he sucked at math and suddenly the problem was a piece of cake.
A lot of math phobia gets swept away when you are presented with problems in a more familiar setting. That’s why I know my students don’t suck at math, or at least not nearly to the degree they think they do. After all, math is hard, but it’s a skill you can learn.
I’ll wrap this up with a video that caught my eye this morning that dispels a lot of the myths, fears, and misconceptions about math. I’m not a genius at math by any means, and I might have to stop and think a little bit more when solving a problem than others. But I don’t suck at it, and neither do you.
I realize that there are no shortageofreviews of last night’s premiere of Cosmos: A Spacetime Odyssey (including one by my good friend Mike Brotherton), but I did have a few thoughts of my own. First and foremost, I loved this show. It was beautiful and poetic, thoughtful and insightful, and firmly made the case that science is the only way to really understand the world and universe we live in. Will I love it as much as Carl Sagan’s original? Maybe, maybe not, and truthfully, I’m ok with either outcome.
Although Sagan is no longer with us, having his protege Neil deGrasse Tyson at the helm of the new Ship of the Imagination is a fitting passing of the torch. And what better way to begin the new voyage than with an homage to Sagan. I couldn’t imagine a more fitting kickoff to this series than to literally begin at the same location Carl did 34 years ago.
But in that time a new audience has grown up that is inundated with even more television channels and production values that far surpass anything Hollywood was capable of producing in 1980. Make no mistake, the production values of the original Cosmos were, in my opinion, absolutely incredible. I truly felt like I was flying through the universe with Carl on his ship. Even though there is no way they could possibly do a poor job with this new production, I was wondering if the new series might go overboard with the use of visual effects, or use them in a way that has, quite frankly, been done to death in other science programs. The answer, to be honest, was a bit of a mixed bag for me.
Cosmos sets out to orient the viewer in much the same way as it originally started out – by describing our place in both in space and in time. The space bit had Tyson and his ship zipping through the Solar System, which was fine until…
To be fair, they didn’t show the Ship zigzaging around the asteroids in hairpin tuns a-la the Millennium Falcon in Star Wars: The Empire Strikes Back; This shot was much more graceful than that, suggesting perhaps a little bit more space between the asteroids. But the truth is that asteroids are already very, very far apart from one another. I personally would have much preferred a setup where the audience thinks they’re about to play cosmic dodge ball, only to discover that the asteroid belt is wide open with nothing in sight, and Tyson actually having to set course to fly by an asteroid in order to glimpse one up close. That might not have been as visually stunning, so it looks like they went for the cool shot instead, but they also reinforced a very common misconception.
Things get much more interesting – and pretty accurate – when passing through the Jupiter system. The sequence of flying through the Great Red Spot absolutely blew me away.
Of course, you can’t do a Saturn flyby without going through the rings. I’ve heard some complaints that they didn’t get the scale right here, but the thickness of Saturn’s rings vary from as thin as 10 meters to as thick as 1 kilometer.
All things being equal, this was just too cool a shot to pass up, so I’m good with it.
Next was an all-too brief mention of the ice giants Uranus and Neptune. I know it’s an ambitious first episode show and there’s only so much time to devote to such things but I feel bad for those two worlds. To their credit, they took a moment to describe Trans-Neptunian Objects and the icy worlds of the Kuiper Belt, but once again they overcrowded the scene.
It seems that in this new sequence, we are dodging space rocks a-la the Millennium Falcon, which is unfortunate. In reality, there’s even more space between Kuiper Belt objects than there are between asteroids by virtue of the fact that the Kuiper Belt extends so much farther from the Sun than the asteroid belt. Alas, the cool shot wins out and a misconception is reinforced. Bummer.
Interestingly, as Tyson leaves the Solar System, he looks back on the Oort Cloud and notes that the objects there are as far apart from one another as Earth is from Saturn. I guess that’s why he didn’t have to dodge them on the way out. My only observation here, as with any depiction of the Oort Cloud, is that at this imagined distance, the icy comets that populate the cloud are much too small to be seen; The Oort Cloud would be no more noticeable from outside the solar system than it is from our vantage point well within it. And yet there needs to be a way to visually communicate to the viewer that they’re there, so we get a delicate sphere around the Sun.
Jumping forward in the sequence, Tyson continues to define our cosmic address through our diminishing place in the Virgo Supercluster of galaxies. Whenever I see shots like this, I get goosebumps, despite having been familiar with the scale of the observable universe for most of my life. However, I’ll just note that if we really were as far out in between galaxies as depicted in the sequence, we wouldn’t be able to discern each individual galaxy with our own eyes. Remember, each galaxy in an image like the Hubble eXtreme Deep Field is the result of 2 million seconds of exposure time – nothing our eye would ever be able to register in a glimpse, even if we were looking through the Hubble Space Telescope itself. Still…goosebumps!
It’s when we zoom out to the large scale structure of the observable universe that we finally complete our cosmic address.
I’m not sure why they chose to represent this as purple in color, but my guess is that it was inspired by the Millennium Simulation Project, an ambitious model of the gravitational interaction of a whopping 10 billion galaxies. Here is a small piece of their result:
To tell the truth, I wish they had used this image instead of the one they created. Not only is it more realistic, but it makes the observable universe seem larger than it appeared in Cosmos.
When describing the history of the universe, we are (re)introduced to the analogy of an earth calendar. I always thought this was the best way to convey the 13.8 billion-year history of the universe, and the comparatively negligible length of time humans have been around to notice it, to a lay audience. Naturally, this has to start with the Big Bang which, unfortunately, cannot really be properly described even with the most sophisticated of visual effects.
Don’t get me wrong, it was a cool sequence. The problem is that you cannot really depict spacetime expanding into itself, which is what really happened (and is continuing to happen). That’s because there is no outside for the universe to expand into. Perhaps the most accurate way to depict a Big Bang is to show nothing on screen, then show “fire” everywhere. There was a 1991 documentary called The Astronomers that depicted the Big Bang exactly this way. But it’s hard to convey the idea of a massive explosion without showing something…well…exploding. Hmm…
Truth be told, I’d be ok with this had Tyson not made the statement that in the beginning the entire universe was compressed down to the size of an atom. If he had instead said it was the observable universe that was so compressed, it would have made all of the difference. Here’s why:
Most cosmologists generally believe that the universe is infinite. By that definition, it extends farther beyond the farthest points in space we can see. These farthest points define the observable universe, and Tyson makes a point of distinguishing the observable universe from the entire universe, which is infinite.
But here’s the catch – if the entire universe is infinite today, then it must have been infinite in the beginning as well. But how can something be both infinite and compressed down to the size of an atom? It can’t, but the part that defines today’s observable universe can, with all of the points of the infinite universe beyond compressed next to it, and so on. Here’s an illustration from Edward Wright’s excellent cosmology FAQ:
The green circle represents our observable universe, with the galaxies (dots) much closer together a billion years after the Big Bang than they are today. If we run the clock back further to the beginning, our green observable universe would be infinitesimally small, but the dots (representing the galaxies we will never see) will still go on forever.
Alas, by stating that the entire universe was compressed to the size of an atom, I think Tyson may have reinforced a major misconception.
Again, none of this is to take away from what I thought was an amazing production. And truth be told, we need Cosmos on our screens now more than ever. Carl Sagan presented Cosmos at a time of both great exploration of our solar system and of grave danger to our home planet and to humanity’s own existence. Sagan understood that our very survival depends on humankind’s knowledge of the cosmos, and of our place in it.
Today, we find ourselves once again in peril – perhaps not from nuclear annihilation but certainly from a rapidly warming planet – but now amid an ever-increasing wave of science denial. Denial of global warming, modern medicine, biotechnology, and of investments in research. If there was ever a time when we need to present Cosmos to a new generation, it’s now.
You can view the entire episode here. Enjoy the journey.
“The purpose of life is to live it, to taste experience to the utmost, to reach out eagerly and without fear for newer and richer experience.”
Would you take a one-way trip to Mars? Think about that for a moment: would you leave your family, friends, the entire planet Earth behind to live out your days forever enclosed in a sealed habitat on a distant planet, entirely dependent on your fellow colonists and resupply ships from Earth? Here are some people who say they will:
It’s a thought-provoking short film which gives insight into the type of people who are willing to undertake such a journey. All of them applied to Mars One, an ambitious program to select and train the first human colonists to live out their lives on Mars. There are many reasons why this would have to be a one-way mission, but the short version is that by the time humans get to Mars, there would be no way they could survive a return to Earth. Mars’ gravity is less than ½ of Earth’s. Even if we could somehow simulate that environment on the journey to/from Mars, their muscular/skeletal structures would atrophy far too much to make survival in Earth’s 1g environment possible. That’s why the trip would have to be one-way: permanent exile on Mars.
And yet, for these people, such exile would give their lives tremendous purpose, one far different from those of us who would remain behind on Earth. It’s important to consider this because it shows that in a very real sense, humanity is going to have to change in a fundamental way if we ever become a true multi-world species.
When you have one-thousand thirty eight confirmed exoplanets. you get to do some pretty cool things with all of that data. The Open Exoplanet Catalogue put together a really cool bubble chart of these planets’ sizes and temperatures.
Pretty, isn’t it? And there’s a whole lot of information packed into each bubble. The size of the bubble corresponds to the relative size of the planet and its color corresponds to its equilibrium temperature. We can think of a planet’s equilibrium temperature as an idealized case where the planet is only heated by its parent star, and there is no warming or cooling due to the planet’s atmosphere. Of course, that’s never the case in real life and that’s why the the folks at the Open Exoplanet Catalogue were careful to point out that “green might be right.”
Take a look at the visualization yourself and spend a few minutes (or hours) hovering over the planets. Visualizations like these are a great way to explore large sets of data like these all at once. And with another 1,073 (and counting) unconfirmed exoplanets, there’s going to be an ever-expanding dataset to explore.
For any graduate student or postdoc, teaching is a rite of passage. Lucky for me, I got to experience teaching early on as an undergraduate at Villanova University starting in the late eighties as a teaching assistant for the core undergraduate astronomy lab.
That also happened to be the last time I actually taught astronomy lab until now. I’ve done my fair share of public outreach, informal educational activities, school partnerships, and even a weeklong cram astronomy workshop, but formally teaching for realz for a full semester at a university is something I haven’t done in over 20 years, until now.
Last night I taught the first of 12 labs for Astronomy 161 at Towson University. Now, I don’t plan on telling any war stories, but if last night is any indication, there may not be any war stories to tell anyway (I know, famous last words.)
As a subject, astronomy is one of the most counterintuitive to us. It requires to contemplate the greater universe far beyond the trappings of our day to day world. Consider these “simple” questions:
Which direction is East?
Which direction is West?
Where is the highest star in the sky?
Right off the bat, we’re faced with questions that have no bearing on our everyday experience, yet are fundamentally important to understanding our place in the cosmos.
Unsurprisingly, some people were stumped by these questions at first. But it wasn’t long before the light bulbs started going off and one by one, connections to the cosmos were made right in front of me in that lab.
It feels great to be teaching again and I’m kind of kicking myself for not thinking to do this sooner, seeing as I loved it so much going back to my undergrad days. Oh well, I’m here now at Towson and I’m looking forward to the rest of the semester.
To any of my students who might be reading this post, welcome! Feel free to grab a Astr.161 Syllabus in case you didn’t get it from the school’s Blackboard site (which is something else I’m trying to figure out – these new fangled computer internets and all…)
Oh, and feel free to leave your answers to the above questions in the comments below
We had some time to kill today, so Tom Wolf and I made a little video to explain today’s launch postponement. Since making this video, we learned that launch is GO for tomorrow, so yay! My full post is below, but in the meantime…
I woke up this morning in my hotel to a beautiful, albeit cold, morning on Chincoteague Island, VA. I glanced at my email only to discover that today’s launch had been postponed. It wasn’t a problem with the Cygnus spacecraft, nor the Antares rocket, nor (thankfully) a new problem on board the International Space Station. Everything was perfect down here on earth.
But in space, the weather was absolutely horrible. Here’s why:
Holy mother of all sunspots, Batman, those are HUGE! To give you an idea of just how large we’re talking about, let’s make a little comparison for scale:
Those sunspots are the reason for today’s postponement. Sunspots are regions of angelic instability on the “surface” of the Sun. They mark the locations of magnetic field lines that rupture, unleashing a storm of charged particles into space at speeds of up to 2 million miles per hour. Those particles strike Earth’s magnetic field, giving us aurorae at the north and south poles:
Unfortunately, that means a lot more radiation in the near-Earth environment, and this poses a problem for launch. The Cygnus spacecraft is “hardened” against radiation, but the Antares rocket isn’t, and the launch team were concerned that it might play havoc with the rocket’s avionics, hence the postponement.