Check out episode 5 of Walkabout the Galaxy and subscribe to our podcast. In this episode, guaranteed to be the newest one until the next episode, Josh, Addie and Tracy discuss the original Wiener, getting sliced into tiny pieces, and then there’s a bit about the LADEE mission to the Moon as well.



Average Rating: 4.7 out of 5 based on 174 user reviews.

Posts here have become an increasingly rare item. Here, in a nutshell, is what is going on. In January 2011 I became Associate Chair of the Department of Physics at UCF. In September 2011 I became Assistant Director of the Florida Space Institute. Meanwhile I’m directing the Center for Microgravity Research and Education at UCF as well as carrying on my regular research and teaching duties. Things have been going very well on all fronts, but posting here has fallen through the cracks a bit. On my “pending posts” list are reviews (now unlikely to ever be written) of movies seen several months ago, such as “The Descendants”, “Unknown”, and “Drive”.

In March our Microgravity Center got three important wins from NASA’s Flight Opportunities Program providing us with a week-long parabolic airplane flight campaign for one experiment and two suborbital rocket flights for each of two other experiments. Florida Space Institute’s new digs at the UCF Research Park are well into construction with an anticipated move from Kennedy Space Center in June. The Physics Department continues to modernize its teaching program with the development of a new modern “studio-mode” classroom to be built this summer, and I completed my first year of teaching the Algebra-based Physics 1 and Physics 2 cycle (physics for life sciences majors) just this week. Cassini, meanwhile, is getting ready to leave Saturn’s equatorial plane for more inclined climes this summer, providing us once again with dazzling views of the rings and me with a new flood of data to analyze.

And, finally, the astonished amusement phase of the presidential campaign now gives way to the obsessive panicky phase at the prospect that election-law tinkering, super-PAC spending, and propaganda will result in the dismantling of the American government.

Average Rating: 4.5 out of 5 based on 241 user reviews.

I was happy to see the publication of Lab Coats in Hollywood: Science, Scientists, and Cinema by David A. Kirby. David interviewed me years ago about my experience as a scientific consultant on Deep Impact as he was conducting research for this book. The final product is comprehensive and an interesting read.

Average Rating: 4.8 out of 5 based on 163 user reviews.

Nearly a month since my last post due to two things: I haven’t seen a movie in a theater in that time, and it has been an insanely busy time at work. I am teaching a new course and have had a number of review writing and other deadlines. On the research front, work continues on the Microgravity Experiment on Dust Environments in Astrophysics, a somewhat awkward name that allows us to use the more convenient acronym MEDEA. I’ve created a Facebook group: The Colwell Research Group. This will have images, data, video, and other updates on my own research. Please look us up and “like” us if you’d like to follow along with our research activities.

On the Cassini front, we are now in the Cassini Solstice Mission: the second and final extension of the mission. However, this extension exceeds both the prime and first extension in total length, with a finale around lunch time (1:00 p.m. Eastern) on Friday September 15, 2017 as Cassini dives into Saturn’s atmosphere. For the next year and a half, though, Cassini is in Saturn’s equatorial plane meaning there won’t be much in the way of observations of the rings for a while.

Star Trek: I used to be an avid player and tournament director of the Star Trek Customizable Card Game. For a variety of reasons, including embezzlement at the company that made the game, it eventually stopped production. Recently I learned that a group including some of the game’s designers is keeping it alive and that there is a small but vibrant group of players here in Orlando. It is a great hobby and is now once again sopping up spare minutes of my time (and giving my head a much-needed diversion from work in the process).

Average Rating: 4.6 out of 5 based on 176 user reviews.

It is an occupational hazard of an astronomer to be asked about the supposed catastrophe(s) in the year 2012. Usually people want to know about the effects of the alignment of the planets in that year. Sometimes, prompted by the movie 2012, they mention neutrinos. Even if they don’t think the world will end, they are surprised when I tell them that there is no planetary alignment in 2012, and uncomprehending when I point out that it would not make a bit of difference if there were.

Here is a movie of where the 8 major planets are from 2000 through 2050 (click the link to open and play the movie; use the controls to scroll through and pause on any year, displayed at lower left).
Motion of the Planets from 2000 to 2050
Notice how closely spaced the four inner planets (Mercury, Venus, Earth, and Mars) are compared to the outer four. Notice also the frenetic pace of the inner planets. Clearly it’s not too rare for Earth and its terrestrial neighbors to be roughly lined up simply because they are all orbiting the Sun relatively quickly. And just as clearly, with its 165-year orbital period, Neptune (the triangle on the right side of the movie) is not very frequently in line with the rest of the planets. There is a much more impressive alignment of the planets, in fact, in 2010 than in 2012.

And just what are the implications of a planetary alignment? For the outer planets, it means skygazers will have a nice view of several planets each night, as they will all be up in the night sky at about the same time. That’s about it. If we tally up the ways planets could interact with us here on Earth, we come to a pretty short list:
– they reflect sunlight toward the Earth
– they have a gravitational effect on the Earth
Their magnetic fields do not extend to the Earth which is, anyway, enclosed in its own relatively strong magnetic field. The amount of sunlight coming to us from the planets is obviously puny and generally less than many stars.

For their gravitational influence, we can do a simple comparison. The gravitational acceleration exerted by an object on you or me is proportional to the mass of that object divided by the square of the distance between you or me and that object. So, for Jupiter, the most massive (and relatively nearby) planet, the gravitational acceleration you feel due to Jupiter’s presence is proportional to Jupiter’s mass (1.9 times 10^27 kg) divided by 3.9 times 10^25 meters squared. That gives us 48 in our units (where we are not worrying about the universal constant of gravitation since it will drop out when we make our comparison). Let’s compare that to, say, the acceleration you feel due to the gravitational influence of your spouse. If your spouse or significant other is a rather svelte 110 pounds (50 kg) and is sleeping 1 meter away from, then the gravitational acceleration you feel from that person is 50 divided by 1 squared, or 50, roughly the same value as the entire planet Jupiter. To pick a more dramatic example, when you stand next to your car, it is exerting a far greater influence on you (about 40 times greater) than all of the planets in the solar system. But then, you knew that, didn’t you?

The two astronomical objects that do produce a noticeable gravitational effect down here on the surface of the Earth are, not surprisingly, the Moon and the Sun. And when they line up it does have a measurable impact: the so-called “spring tides” or “full Moon tide” and “new Moon tide”. The gentle rising of the ocean up the beach every six hours or so is due to the tidal force of the Moon, and tides are simply due to the difference in the Moon’s gravitational pull across the body of the Earth. The Sun, although more massive, has a somewhat smaller effect on tides than the Moon because it is so much further away. But when the Sun and Moon are aligned (at full Moon and new Moon), their tidal effects combine and ocean tides are higher than usual. In the units we computed gravitational acceleration above, where Jupiter and the person standing next to you both rate about a 50, the Moon’s effect is about 460, 000 and the Sun’s is 9 billion. The Earth does go around the Sun after all. (Tidal force depends on the derivative of gravity and so gets weaker with distance faster than gravity, hence the weaker tidal influence of the Sun than the Moon.)

So catastrophes in 2012 are likely to be restricted to homebound, terrestrial causes (hurricanes, earthquakes, volcanoes, famine, drought, floods, and elections). The only sky-based catastrophe possible would be the impact of a comet. A catastrophic asteroid impact in 2012 is unlikely because we have much better advance warning for asteroids than for comets due to the shapes of their orbits (comets can sneak in from the outer solar system, while we have observed most dangerous asteroids).

Average Rating: 4.5 out of 5 based on 184 user reviews.

The first Next-Generation Suborbital Researchers Conference just concluded in Boulder, Colorado with a larger-than-anticipated turnout (250) including movers and shakers from NASA, the commercial launch industry, and the scientific community. The Conference was an interesting mix of programmatic presentations from NASA, which has proposed $15 million/year for research missions on commercial suborbital vehicles (think SpaceShipTwo from Virgin Galactic, or New Shepard from Blue Origin), presentations from the many companies involved in the commercial launch sector, and an eclectic mix of scientists and educators looking for ways to utilize this new capability to reach the lower bounds of space. By all accounts, including mine, the meeting was a resounding success. Which of course just raises the expectations for next year’s conference which is being organized by – wait a minute, this can’t be right: by me! So mark your calendars for February 28 – March 2, 2011, on the main UCF campus in Orlando for the second go-round. By then, commercial suborbital vehicles may be flying to space.

Average Rating: 4.6 out of 5 based on 275 user reviews.

Day 2 was all about the Phoenix centrifuge at NASTAR. After some instruction on techniques to increase blood pressure to avoid loss of vision and black out, we did a series of four flights in the morning. Because the centrifuge only accommodates one person at a time, and because there were a dozen of us, it took a while for everyone to get a ride. I was fifth to go. The four flights consisted of brief profiles of sustained acceleration along either the body’s plus X axis (into the chest) or the plus Z axis (down the spine). The latter pose problems for consciousness because +Gz makes it harder for the heart to pump blood to the brain. The Gx flights make it difficult to breathe, but are not generally likely to make one pass out, at least for the durations we were doing (about 20 seconds at a time).

I have previously had experience with two G’s on parabolic airplane flights. The first time I flew one of those flights, I oriented my body so that the two G’s were in the +z direction, and I got very sick after about a half dozen parabolas. On subsequent flights I lay flat on the floor of the plane, making those G’s in the +x direction and therefore much easier to bear. So I was concerned about our 2 Gz and 3.5 Gz flights, though they wouldn’t have the repetition of the “vomit comet” nor would they be interspersed with 0 G parabolas. On the 3.5 Gz flight I had to apply all of the body-tensing countermeasures we used because I started to get a bit of tunnel vision. The countermeasures worked. The Gx flights, at 3 and 6 G’s, were impressive. The sensation of going up very very fast was completely convincing. At 6 Gx it was a real effort to breathe, and speech was very difficult. All in all, the flights were smooth and didn’t make me sick.

In the afternoon we did two flights simulating the acceleration profile of Virgin Galactic’s SpaceShipTwo. One was at 50% of the total acceleration, and the other was full acceleration. These profiles involved both Gx and Gz at the same time, along with a visual simulation of what we would see through the window of the spaceship. These flights really gave the impression of going somewhere FAST. On the final run, I had to apply countermeasures to keep my vision as things started to go gray during the 3.8 Gz portion of the rocket burn. The peak accelerations are actually on re-entry, but they are Gx and so are easier to deal with.

Average Rating: 5 out of 5 based on 198 user reviews.

Today we got a tour of the NASTAR center which has some impressive aircraft simulators and a gigantic centrifuge (11 ton, 25-foot arm, with bolts going 45 feet down into the bedrock and a huge mass of concrete underneath to keep it stable as it swings around). Then we had a course on the physiology of hypoxia (oxygen deprivation) and some basics on atmospheric physics before getting fitted with oxygen masks and heading for the altitude chamber. I’m not actually sure that’s the write term, but it’s a room with a dozen seats and ports for oxygen masks and can have its pressure adjusted to simulate various altitudes.

After 30 minutes of denitrogenation (breathing pure oxygen to remove nitrogen bubbles from the blood to reduce the likelihood of those bubbles expanding to painful size on ascent to high altitudes), we took our masks off and they took the chamber up to 18, 000 feet. That is to say, they lowered the pressure in the room to what it is at an altitude of 18, 000 feet. At that altitude, the pressure is about half what it is at sea level. So each breath delivers half the oxygen of a breath at sea level. We had some simple exercises to perform – simple math operations, some writing – to identify any degradation in mental function as we entered a hypoxic state. I noticed an increased heart rate, but no other symptoms. I have done two altitude “flights” in the past, about 10 years ago, with no noticeable effects. I could not tell if the increased heart rate was due to lack of oxygen or simple anxiety about possibly worse effects. After about 15 minutes, one member of our group passed out. By that time I was feeling a bit tired, but otherwise no overt effects of hypoxia. My simple math problems were done without error, as were the two mazes.

Average Rating: 4.7 out of 5 based on 178 user reviews.

Today I flew to Philadelphia with my graduate student, Akbar Whizin, in preparation for a two-day course on suborbital spaceflight at the NASTAR center. With at least two companies readying commercial suborbital rockets to carry paying passengers to the lower limits of outer space, there is increased interest in the uses of these vehicles for science and education and not just high-priced sightseeing. NASA has long had a vigorous program of experimentation in suborbital sounding rockets. These new vehicles may soon find a place as laboratories for scientists and students who need quick and easy access to either the upper reaches of the atmosphere or a few precious minutes of high quality microgravity.

My own scientific interest in these vehicles lies in the study of the collisional behavior of small objects and aggregates of objects at low impact speeds. I’ve had one such experiment fly twice on the space shuttle and a similar experiment has flown several times on parabolic airplane flights. These experiments simulate in various ways the collisions that were common in the early stages of the formation of the solar system and are currently taking place in Saturn’s rings (and the rings of the other planets). It is not possible to perform experiments on these kinds of collisions without a microgravity environment. A few seconds of microgravity can be achieved in a drop tower, and 10-15 seconds of a relatively uneven low-gravity environment can be obtained on parabolic airplane flights. For many experiments a longer, more stable microgravity environment is needed.

Virgin Galactic has unveiled the first of its passenger-carrying suborbital crafts, the VSS Enterprise. Blue Origin has selected my experiment and two others to fly on a test flight of their New Shepard suborbital rocket. Other companies are developing rockets for passengers and some just for payloads. Someday soon, scientists may be flying alongside their experiments on these rockets, reacting to the performance and making real time adjustments to the operation of the experiment. And so I find myself getting ready to undergo two days of “astronaut boot camp” at the NASTAR center. Tomorrow features some hypoxia training and time in a chamber simulating high altitudes (low atmospheric pressure). Wednesday will be a full simulation of a flight on the VSS Enterprise. The final frontier awaits.

Average Rating: 5 out of 5 based on 297 user reviews.

With the 40th anniversary of Apollo 11 I have heard more than I care about the delusional segment of the public that insists we did not go to the Moon. Only for my peace of mind, I have imagined a conversation with a Moon landing conspiracist where I ask him if he believes people have been to Antarctica. (My satisfaction in this imaginary conversation depends on him saying “yes, ” but the beauty of me imagining this conversation is that I do, in fact, get to decide what the other person says.) So he says “Yes, of course!” to which I reply, “Why?”. Well, you can imagine the responses to this as well as I can, because presumably you also believe people have been to Antarctica, and unless you have personally been there yourself (and I know some of you have), all your reasons for believing people have been to Antarctica are the same as the reasons for believing people have been to the Moon: we have seen pictures of people there; we have talked to people who have been there; we have seen things that were brought back from there; we have seen the machines that take people there. Qualitatively, (unless, again, you have been there yourself), there is no difference in the evidence for people going to the Moon and the evidence for people going to Antarctica. My imaginary debater can then only fall back on the idea that going to the Moon is implausibly hard, to which I wonder if he believes that I can store thousands of books, pictures, songs, and movies on a device the size of a matchbook and why he thinks that is easier that sending a rocket to the Moon. In my imagination, my foe is crushed on the withering force of my logic. In reality, of course, there is just no arguing with some people.

Average Rating: 4.7 out of 5 based on 181 user reviews.