Archive for the ‘Science - General’ Category

Parabolas: 15. Vomit: 0

Thursday, December 11th, 2008

I completed my seventh lifetime parabolic flight on Sunday, but first flight with the Zero-G corporation. While my earlier flights on NASA’s KC-135 (now retired and replaced by a C-9) involved anywhere from 36 to 51 parabolas, Zero-G does only 15 parabolas on non-research flights. They also currently have a contract to sell flights to NASA, and I think those do the full set of 40-50 parabolas, but the flight I was on Sunday was sponsored by Space Florida for educators, and operated in pretty much the same mode as their passenger flights. The limited number of parabolas is to limit motion sickness. As someone who has gotten violently ill on the longer flights, I think this is a good idea. Paying five grand (their current ticket price) to get violently ill, even with the unique experience of weightlessness, would probably leave a lot of customers grumpy.

Their flight plan begins with one parabola simulating at martian gravity followed by two “lunars”. Parabolas are flown in groups of three followed by a couple of minutes of straight and level flight to get set up for the next set.

ZG-210 Silver Team
The Silver Team poses in front of “G-Force-One” prior to our flight on Sunday December 7 at the Space Coast Regional Airport.

I took on board one of the impact experiment chambers from my earlier “Physics of Regolith Impacts in Microgravity Experiment” (PRIME) to do a test run. The experiment basically consists of shooting a marble into a tray of sand at very low speeds in microgravity and measuring the speed and quantity of material ejected. However, because this was being flown as a commercial flight rather than a government flight, it was not possible to evacuate the test chamber. The test material floated out of the target chamber, limiting the amount of ejecta. However, this provided a fairly dramatic demonstration of the effects of air as a lubricant for granular materials and underscores the need for evacuated test chambers on future flights.

PRIME Experiment on ZG-210
I give the thumbs up after successful operation of the PRIME test.

I also tried to do a simpler experiment for classroom demonstration of equipartition of energy in a granular gas. That’s a fancy way of saying “watching different-sized marbles bounce around at different speeds”. This was compromised by the lack of foot restraints on the plane and the general chaos of floating bodies throughout the plane volume. Nevertheless, I think I got some good video.

Granular Experiment on ZG-210
My marble experiment is behaving fine, but my body won’t hold still.

Weightlessness at 25,000 Feet, Give or Take a few Thousand

Friday, December 5th, 2008

Sunday December 7 I’ll be flying on the Zero-G Corporation’s “G-Force-1″ airplane (a modified Boeing 727) out of the Space Coast Regional Airport. The pilots of G-Force-1 fly the plane as close as possible to a perfect parabola at a constant horizontal speed and a constant negative acceleration of 9.8 meters per second squared. That is, they make the plane follow the path of a freely falling object. Because all objects, regardless of mass, fall at the same rate (remember Galileo and that famous leaning tower), I and everyone else inside the plane will be in a state of freefall for about 25 seconds per parabola. During that time we will experience the same sensation as astronauts orbiting the Earth.

At the end of each parabola, the plane must accelerate upward giving us a weight of about 1.8 times normal (or 1.8 g’s). During one parabola I’ll be testing a modified experiment on the formation of planets. In particular, I’ll be studying the effects of low-speed collisions between a large object and a collection of small particles to see how well things stick together or blow apart when gravity isn’t present to hold them together. I have done similar experiments on NASA’s version of G-Force-1 before (affectionately known as the “vomit comet”). NASA’s plane typically does 45 parabolas per flight, while Zero-G is kinder to its passengers and limits the parabolas to one simulating martian gravity, two simulating lunar gravity, and 12 zero-g parabolas. With that profile, I am confident I will avoid the upset stomach that plagued me on flights on NASA’s plane.

Alan Stern Leaves NASA

Thursday, March 27th, 2008

Alan Stern resigned as NASA’s Associate Administrator of the Science Mission Directorate. In his short tenure as AA Alan had embarked on an ambitious program to overhaul how SMD operates. Speaking from the perspective of a university researcher, his changes to the Research and Analysis programs were a great improvement: faster and better communication between NASA HQ and proposers, longer terms for typical awards coupled with new “on-ramps” for young researchers, new science programs to capitalize on the new exploration initiative, and new programs for small space experiments, such as sounding rocket experiments. Of course, anytime there is something “new” without an increase in the budget means there’s going to be a cut to something “old”. Alan addressed the American Astronomical Society’s Division of Planetary Sciences meeting last October and said that in a zero-sum budget environment, his plan to get new missions and programs started was to hold the line on budget overruns on existing programs. Many high profile missions are running over their budgets. His departure suggests that he may not have had the flexibility he needed to deal with those cost overruns. Hopefully some of the changes he did manage to institute during his short tenure will persist into the new administration.

Evolution in Florida

Friday, February 22nd, 2008

Florida’s State Board of Education voted (4-3!) this week to include evolution (for the first time!) in the science curriculum of public schools. (Previously the concepts of evolution were taught in Florida, but the curriculum referred only to things such as “change over time”. My own recollecton of Honors Biology in a Florida High School are that our class had a debate on the topic of evolution. I was one of three or four on the side arguing in support of evolution, and the opposing group argued for Biblical creation. I do not recall any instruction on the matter in class at all.) The new standards were apparently headed for defeat until a so-called compromise was reached by inserting the words “the scientific theory of” before the word “evolution”. This concisely illustrates the anti-evolution advocates’ lack of understanding not only of evolution but also of what “scientific theory” means.

50 Years After Explorer 1

Friday, February 1st, 2008

The United States entered the space race 50 years ago today (okay, I wrote this on the anniversary, but am posting a day late) with the successful launch of the Explorer 1 spacecraft. Although Explorer 1 was a modest 30 pounds and quite simple by the standards of today’s spacecraft, it made an important scientific discovery. The spacecraft was built at JPL, where I happen to be at this moment for a Cassini Project Science Group meeting, and where there is a distinctly festive air and displays of the history of JPL’s involvement in the U.S. space program. The key instrument on Explorer 1 was a Cosmic Ray Package that was essentially a Geiger counter for detection of charged particles. The flux of charged particles was much less than expected at high altitudes (>2000 km), but equal to the expected value at lower altitudes. James Van Allen, lead instrument scientist on Explorer 1, hypothesized that the instrument was saturated by radiation from charged particles trapped in the Earth’s magnetosphere at high altitudes. The confirmation of this by Explorer 3 a few months later earned these regions the name they are still known by: the Van Allen radiation belts. Because of the high energy of the particles in these toroidal regions around the Earth, they pose a hazard for astronauts as well as spacecraft electronics. The space shuttle and space station orbit safely beneath the belts. Pics of the festivities at JPL coming shortly.

Hmm. I think the pictures are on my phone, but they didn’t translate to my computer last time I synched.

Chimpanzee Memory Tests

Wednesday, December 5th, 2007

These amazing video tests of chimpanzee visual recall show to my amateur eye that chimps process and retain the visual field in a way that is different than humans. Some explanation and commentary on the significance of the results can be found in this New Scientist article. As Darth Vader said, “Impressive. Most Impressive.”

Science and Hot Tempers

Sunday, December 2nd, 2007

Apparently there’s nothing like a post on UFOs and conspiracies to boost the number of comments on my blog. In response to this post on the burden of proof, one commenter says:

If you actualy believe that there is life on other planets, get out of your dream world and stop being such an idiot!

and

To believe that there is life on other planets, you need to believe in evolution. By the way…… there is no proof for evolution!! All evolution is is another religion, because you have to believe it, without any physical evidence! so stop acting like it is science…because its not!!

Everything he says is incorrect, though the implication in the third sentence that religion is something one believes without physical evidence is reasonable. Of course, one does not need to accept the fact of evolution to believe that there is life on other planets. Presumably the idea is that life was created on Earth by a deity, but to believe that deity created life only on the Earth in a universe with over 100 billion galaxies containing roughly 100 billion stars each is to have a very restrictive view of that deity’s powers as well as presuming it to be something of a wasteful, or at least mischievous, creator. I am sure there are many people who believe that some god or other created life on many worlds. Whether or not they also understand evolution is irrelevant.

As for proof of evolution, I refer the reader to any biology textbook as well as many fine museums. There is so much physical evidence for evolution, that to deny the existence of the evidence reveals a willful determination to ignore reality. As for life elsewhere in the universe, my expectation that it exists is based on scientific speculation, but certainly not on physical evidence, and perhaps this is what irked the person quoted above. In fact, when I reread what I wrote I expected to find that I had written that I “believed” there was life elsewhere in the universe. Instead I wrote

I would be thrilled by the discovery of extraterrestrial intelligence, but so far there is no evidence…

In fact, I do believe that there is life elsewhere, but what I believe is irrelevant to scientific inquiry. That’s the whole point of science: to advance understanding through observation and experimentation, in short, through evidence. This is also why the word “belief” is irrelevant to the question of evolution. It is based on evidence, not belief. The evidence is also that the Earth is not unique and that life developed on it through natural processes and that the laws of physics are the same throughout the universe. It is therefore a reasonable hypothesis that life exists elsewhere, and that’s why we are looking for the physical evidence through SETI and exploration of our neighboring planets and their moons. The hypothesis will remain a hypothesis until we obtain evidence. A persistent absence of evidence would be reason to discard the hypothesis, but we are so far from being able to explore other Earthlike worlds that it will be a long time before we can reject the hypothesis that there is life elsewhere.

UFOs and the Burden of Proof

Friday, November 16th, 2007

Yesterday I attended a short speech given by former Apollo astronaut Dr. Edgar Mitchell at the University of Central Florida. Mitchell presented a scholarship to a UCF Engineering student and then gave a brief description of his career as an astronaut culminating in two 5-hour sojourns on the lunar surface as part of the Apollo 14 mission. Mitchell, with a Sc.D. from the Massachusetts Institute of Technology in Aeronautics and Astronautics, then expressed his concerns and hopes for the future of humanity: concerns that we will destroy ourselves as our technological capabilities advance faster than our sensibilities, and hopes that we will survive these dangers to continue exploration of the cosmos. They are good and noble sentiments, and I appreciate him expressing them and pointing out that when the Earth is viewed from afar, as only he and a handful of other men have done, national boundaries evaporate and the precarious and unique status of the Earth as home to all life becomes painfully clear.

In response to questions, Dr. Mitchell expressed that aliens have visited the Earth, and while he wasn’t explicit, implied that they are living among us and concealed from us by a vast cover-up. He also affirmed that he had successfully communicated through ESP while on the surface of the Moon and that quantum mechanics now explained how this could happen. And this brings me to the criticism from “Object Reporter” on my post a couple of days ago in which I expressed dismay in a new call for government-funded research into UFOs. Object Reporter says I am uninformed on the topic of UFOs and accuses me of spouting nonsense. I stand by my statement that aliens are the least probable explanation for UFO sightings. While it is physically possible for aliens from another planet to visit Earth, there is no compelling evidence that that has ever happened. And compelling evidence is required for such an extraordinary claim. It is an extraordinary claim because the amount of energy needed for interstellar travel is huge, and a visit to the Earth by aliens would represent a huge investment of resources. For them to make this investment and then hide, but hide poorly, does not make sense. They hide poorly because somehow, while they escape detection by the vast network of aircraft and spacecraft tracking systems as well as the vast majority of the population including people like me who would be thrilled to meet them, they apparently occasionally make themselves plainly visible to some casual observers. Other explanations are more likely because in the vast majority of UFO sightings, ordinary terrestrial explanations for those sightings have already been demonstrated to be the case. If one hundred UFO sightings are demonstrated to be due to weather balloons, military aircraft, meteors, ball lightning, camera flares and other mundane explanations, then it’s likely something like that is the explanation for the one hundred and first. The claim of evidence for extraterrestrials carries the burden of proof. I, happily, do not have the burden to debunk each UFO sighting, anymore than if I claim that there is an underground civilization on the Moon someone else has the burden to prove me wrong. Extraordinary claims require extraordinary evidence. I would be thrilled by the discovery of extraterrestrial intelligence, but so far there is no evidence, and the most likely evidence we’ll get would be an extraterrestrial radio signal.

The idea of a vast cover-up is also extraordinary. Forget for the moment that it is difficult to imagine a motive for a cover-up. The power of people in government is always enhanced by engendering fear in the populace, and fear is presumably one consequence of discovering aliens. NASA has as its mission to look for life elsewhere in the universe, and nothing would boost its budget more than the discovery of extraterrestrial life, even microbial in form. In short, lots of people in government have a self-interest in seeing extraterrestrial life proven, not hidden. But the biggest problem I see with the cover-up idea is how consistently miserable people are at keeping secrets. The most powerful person on the planet, the President of the United States, could not even keep a hotel break-in secret or (in a different incarnation) oral sex. The idea that, for decades, hundreds or thousands of people in the military and government could hide the existence of alien visitors defies reason. As for Dr. Mitchell’s demonstration of ESP, James Randi has a million dollars waiting for anyone who can demonstrate ESP or other paranormal phenomena. No one has succeeded, and by the way quantum mechanics, which beautifully describes the behavior of electrons and atoms, offers no explanation for ESP. Finally, in response to the comment on my previous post that “I wasn’t aware that the three doctors, half a dozen ex-military officials and a former state governor were supposed to be taken lightly…”: it is the claims of these people that aliens are on Earth I take lightly because they do not meet the burden of proof. And by the way, George W. Bush is a former state governor, and I take almost everything he says lightly. It’s the only way to avoid depression. Live long and prosper.

Unreliable Witnesses

Thursday, September 13th, 2007

I hope that my future never depends on eyewitness testimony. Years ago I heard about this study in The Skeptical Inquirer (among many others that scientifically demonstrate just how unreliable eyewitnesses are). A recent article in the New York Times provided this link to the original video. Watching it is even more incredible than I thought it would be on reading it. Knowing what the video is, the test doesn’t work, so I won’t say anymore here. Just watch the video and try to be sure to count every successfully completed pass of a basketball between people wearing white shirts only. The experiment only works if you concentrate on successfully counting the passes by the white team.

Launches and Manatees

Thursday, August 9th, 2007

Attempting to take advantage of our proximity to the nation’s spaceport, we ventured east to the coast to see the recent launch of the Phoenix mission to Mars’s north polar region. The launch was scheduled for 5:26 a.m. local time. Confident that I could get to Cocoa Beach in 45 minutes, and that we were going to a spot slightly closer (Jetty Park), I planned to leave at 4:30. We missed our target departure time by only 2 minutes, but I was sadly mistaken on the time it takes to get Jetty Park. With almost no margin for error, we ended up scrambling to get to a viewing spot on the side of the road a scant 3 minutes before launch. This made for a stressful rather than anticipatory pre-launch wait, but the Delta 2 rocket made a spectacular and rapid ascent through a clear Florida sky, leaving behind enough exhaust at high altitudes to generate a colorful and ring-shaped high altitude noctilucent cloud.

Having learned from our experience of not leaving early enough for a launch, today we set out to Titusville to see the launch of Endeavour to the International Space Station two hours before launch, with a driving estimate to the viewing site of 30 minutes in normal conditions. We had not prepared, however, for the normal driving conditions just to get the five miles from our house to the road that leads to Titusville. Forty-five minutes later, we were still stuck in bumper-to-bumper traffic and had traveled about four miles. This is the kind of thing that will eventually drive me insane. Amazingly, ten minutes and one mile later the traffic opened up suddenly and we were speeding to the private dock where our gracious host, UCF student Nate Lust, was waiting with reserved parking spaces on the edge of the Indian River (the name for the stretch of the Atlantic Intercoastal Waterway between Titusville and Kennedy Space Center). Still, I had not totally exhausted my means of messing things up. There are two shuttle launch pads, 39-A and 39-B. Both are visible from the shore in Titusville, but I could not visually tell which one actually had the shuttle on it. Opinion on the dock was mixed, and I confidently convinced myself (and anyone who cared to listen) that the shuttle was on the pad on the left from our vantage point. Thus, I happily trained my video camera and binoculars on this empty launch pad while the shuttle soared skyward completely out of my field of view. Of course, I quickly turned my gaze, but I missed that exciting first couple of seconds as the steam cloud first erupts and the shuttle with its bright solid rocket motor glare emerges from behind it.

Any disappointment was more than compensated for by the friendly visit of a manatee a few minutes later as we prepared to leave the dock. Anne-Marie’s eagle eyes spotted the manatee, and Nate simply turned on a hose, and the manatee appeared shortly, attracted by the fresh water. Very cool. I’ll post pictures of the manatee and crappy video of the shuttle launch shortly.