Wide-angle, long exposure of a meteor shower.

I get this kind of question on occasion. This time, however, the situation is different. I didn't get this comment via email, or the Ask a Scientist link on Chabot's website, or by phone. The UFO witness in question was, in fact, myself….

Before I go on, I'd like to say that I believe there is probably an explanation for what I saw that doesn't require the existence of extraterrestrial spacecraft. In fact, I don't feel that an extraterrestrial spacecraft is even a good candidate to account for what I saw—so throw it on the list of candidates if you wish.

My parents live in Oroville: it was a nice dark, crystal-clear sky on the evening of October 9th. I was gazing almost directly overhead, in the midst of the constellation of Pegasus—the Great Square, just east of the Summer Triangle, about where the nose of Delphinius the Dolphin is pointing.

Then, suddenly, I saw a star-like pinpoint of light flash into existence, and then out again, gone in the time it takes a star to twinkle once (maybe a half second or less). Wondering if it was a high altitude airplane's head or tail light or a satellite turning and flashing in the sunlight high above, I kept watching, expanding my area of focus to keep it in sight as it moved. But, not only did I find it had not moved much when the flash did reoccur, it in fact had not moved at all: the same point in the sky, not far from a pair of stars in Pegasus, issued the same quick, star-like flash.

Now quite intrigued, I glued my eyes on Pegasus. In the next five minutes or so, I saw five or six more flashes. A couple times they were in the exact same spot as the first two, but in other cases they appeared in different parts of Pegasus, though not far from original location; all of the flashes occurred in an area of the sky smaller than my fist held at arm's length.

Then followed my usual process of trying to eliminate suspects. It wasn't an airplane with a flashing tail light or wing lights (at least, not one behaving conventionally): the flashes were not at regular intervals, and did not fall upon a discernible line or arc as the plane moved.

It was not a low-altitude satellite: Even more than airplanes, these must travel along a line–so even the ones that appear because they have a reflective surface (like a solar panel) and are flashing us as they rotate will appear as a string of flashes, not a cluster of flashes of random brightness and with random and repeating positions. What I saw more resembled the flash pattern of a cloud of broken glass fragments falling in sunlight, almost like glitter.

Iridium satellites exhibit flashes as they turn in the Sun—you can even find out when and where they are going to occur. But Iridium flares occur as a single, relatively slow flash, with evident motion, and they don't occur in clusters.

Very high altitude satellites—those far enough from Earth as to appear motionless—are too far away to normally be visible to the eye. But what about a rotating high altitude satellite with reflective surfaces? Maybe…but again, why a cluster of them? What conditions would make this possibility ripe?

What this left me with, at least on my short list, are point meteors: ones that fly directly toward you and so appear as a point-like flash rather than a moving streak. In fact, while I was waiting for more flashes, I noticed two meteors streak away to the north that actually started their flashy flights right in Pegasus. There was even a meteor shower that was just past its peak: the Draconids, aka the Giacominids. The two I saw were traveling more toward Draco, and not away from it.

Coincidence? Well, to draw on one of my favorite quotes, "I believe that coincidences go on all the time. But I don't trust coincidences."

If they were point meteors, then I witnessed a highly improbably event: six or seven of them within a five minute span, and from a spot on the sky that was not currently the radiant point of any annual meteor shower. What was it, then? A new meteor shower? Less than likely considering the time of night and the apparent radiant point—but I won't strike it from my list.

Believe me, I wish I had an answer for you. Others have reported very similar observations, but also don't have a definitive answer. One thing is for certain: in the future, I will answer other people's questions about "what was that thing I saw in the sky?" with a somewhat more sympathetic predisposition….

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Astrophysicists who track space weather today are at a stage Earth weather forecasters were roughly three decades ago. This is about to change.

I was also surprised to learn how the Sun drives terrestrial weather, the kind that has us grabbing our sunglasses or an umbrella before leaving the house. While producing this story, I interviewed David Dempsey, a Professor of Meteorology at San Francisco University, who illuminated for me the role the Sun plays in this process. According to him, "we wouldn’t have anything we would call weather without the Sun. It shines directly on the lower latitudes of the Earth and less directly at the high latitudes, and that creates a big difference in temperature between the tropics and the polar regions. That difference in temperature in turn creates differences in pressure within the atmosphere that then drives winds. Wherever the air is, it goes up, it cools and you can get condensation of water vapor in the air and clouds form. Clouds then produce rain and they also reflect sunlight back to space, which then modifies the heating of the sun and you have a very complex system taking place across the globe we call weather."

Although weather forecasting has been the subject of much derision, huge strides have been made in weather forecasting, driven by a steady technological progress that has revolutionized the science of meteorology. As Professor Dempsey told me, "we’re probably in the 5 to 7 or even 8-day range as far as making forecasts that have some value to them. Forty years ago, it would have been just a couple of days. Improvements in satellites, in ground-based observations, have all contributed to our better understanding of the state of the atmosphere at any one moment." Take for example COSMIC, six satellites which launched in 2006 and which ingeniously use GPS signals from other satellites to discern the temperature and moisture content of the atmosphere over oceans, which traditional weather balloons, launched from land, can't provide.

Astrophysicists who track space weather today are at a stage Earth weather forecasters were roughly three decades ago when increased computing capabilities allowed them to amass more atmospheric data and analyze the data faster and more accurately. Moreover, with a powerful new tool within their toolkit in the form of NASA's Solar Dynamics Observatory, a satellite that provides a constant, ultra-high resolution view of the sun, the space weather trackers should be able to make more reliable and more detailed forecasts. Phil Scherrer, one of the Principal Investigators on the SDO mission, told me that a reasonable target to aim for is a space weather forecast that would be accurate for roughly a week, which is about what you can expect for a fairly accurate terrestrial weather forecast today.

Today, the stakes couldn't be higher for increased vigilance as our satellites arc through the atmosphere, which for all their state-of-the art ruggedized construction, are still vulnerable to the radiative slings and blows volleying from the Sun. As Professor Dempsey put it, "Solar storms can interfere with our ability to get the data we need, the observations we need, from weather satellites.That can be really critical if you have a hurricane developing off the coast of Florida and you need to know in advance whether you’re going to have all the data you need to try to make your best forecast of the impact of that hurricane. And if you know that you’re going to have an interruption in observations from satellites because of variations in solar output, then you can try to compensate and warn people about it."

Watch the Journey Into The Sun television story online.

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As the impact grows closer, NASA is making an effort to talk about the locally driven mission. Many of the upcoming talks are suitable for any audience, from kids to adults.

Luna Philosophie: Hitch-hiking to the Moon

Where: Scribd, 539 Bryant St. (2nd Floor), San Francisco

When: Wednesday, 9/23 6-8 PM

Cost: Free, RSVP to Delia.L.Santiago@nasa.gov

Details: Dr. Kim Ennico, LCROSS Payload Scientist and the LCROSS Payload Integration & Test Manager, will provide an overview of the NASA LCROSS mission and discuss how NASA has been expanding the concept of “participatory exploration” with LCROSS as an example. This will be a lively discussion.

Andrew Chaikin on LCROSS

Where: Chabot Space & Science Center

When: Saturday, 9/26 3-430 PM

Cost: Free with Museum Admission

Details: Author, speaker, and space journalist Andrew Chaikin joins Chabot visitors for a night of moon conversation and exploration. Using the detailed program Google Moon, which he helped to develop, Chaikin takes the visitor on a guided tour of the moon’s surface. Chaikin will also discuss the recent LCROSS mission and his extensive knowledge of the Apollo missions.

To the Moon: A Look at NASA’s Upcoming Lunar Impact Mission and the History of Moon Exploration

Where: Exploratorium

When: Sunday, 9/27 2-4 PM

Cost: Free with Museum Admission

Details: Take a trip to our nearest neighbor in space with renowned science journalist and space historian Andrew Chaikin. Relive the achievements of Apollo lunar astronauts and learn about the ambitious LCROSS mission, which will send a rocket crashing into the moon’s permanently shadowed regions to kick up huge plumes of debris in the hopes of uncovering deposits of ice. In addition, Exploratorium educators will give an entertaining and interactive overview of moon science.

QUEST on KQED Public Media.

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The Hubble Space Telescope being serviced by Space Shuttle
Atlantis astronauts in May 2009. Credit: NASA

Galileo's telescope had a magnification of only about 27x, allowing him to see that Venus has phases like the Moon, Jupiter has four large moons of its own, Saturn does not appear as a simple disk but has unusual "projections" to either side, and the Milky Way contains far more stars than is apparent to the naked eye. And though these are features that can be seen through the least powerful home telescopes today, Galileo's observations changed the way we look at the universe.

Hubble has done the same thing, but on a modern scale of magnitude. Not a large telescope by the standards of ground-based behemoths like Keck in Hawaii (Hubble's primary mirror is 2.4 meters in diameter), Hubble's "edge" is it's location in space, orbiting the Earth over 300 miles high, outside of our atmosphere. Particularly in its earlier days before ground based telescopes were using adaptive optics techniques to compensate for atmospheric distortion, Hubble's vision on the universe was unparalleled in its clarity.

Here's is a recap of a few of the many big discoveries Hubble has made possible:

Dark Energy: By accurately measuring the distance and velocity of distant supernovae, over a large range of distances, Hubble has refined out knowledge of the rate of expansion of the universe–leading to the discovery that the expansion of the universe is actually accelerating, contrary to what was expected. Scientists suggest the existence of a mysterious "dark energy" throughout the universe that exerts an antigravitational repulsive pressure on the cosmos.

Age of the Universe: Since Edwin Hubble (for whom the Space Telescope was named) discovered that the universe is expanding, astronomers have been trying to determine how long ago the expansion began–how long ago the "starting gun" of the Big Bang was fired, and thus the beginning of the universe. Through precise observations with the Hubble, astronomers in recent years have been able to peg it between 12 and 14 billion years. (Most recently, observations made with the WMAP mission have honed that down to 13.7 billion years, give or take 0.13 billion.)

Supermassive Blackholes: Hubble found the clues that point to the existence of "supermassive" blackholes at the heart of maybe most–or every–galaxy. The Milky Way's own central blackhole has a mass equivalent to four million Suns.

Stellar Dust Disks: Before the first extrasolar planets were actually detected, Hubble observations revealed that flat disks of dust encircling young and developing star systems–aka "protoplanetary disks"–is commonplace. This has given us a glimpse at what our own solar system may have looked like before the planets formed.

It has been seven years since the last Hubble servicing mission, with another servicing scheduled a few years ago cancelled in the wake of the Columbia disaster. Several failing systems will be repaired or replaced this time, and other instruments are receiving upgrades that will make Hubble more powerful than ever in its declining years.

This mission to service the Hubble will be the last. Since NASA is retiring the Space Shuttle fleet after 2010, we will no longer have a space vehicle large enough to carry upgrade and replacement equipment to and from the Hubble. After that, the next new big space-based descendent of Galileo's spyglass will be the James Webb. Stay tuned…

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Cal Poly's CP-4 mini-satellite in orbit. Credit: The Aerospace
Corporation.

It's a classic engineering story – a garage inventor spends years working in isolation, only to produce something that gets the attention of the world. Ok, the CubeSat story may not be quite as romantic, but it does have a lot of the same ingredients.

Professors at Stanford University and Cal Poly created CubeSats – 10 by 10 by 10 centimeter mini-satellites – as enginneering projects to give their students hands-on experience. Compared to standard satellite missions, which can run hundreds of millions of dollars and take years to complete, CubeSat missions are mean to be done cheaply and quickly.

CubeSat is also a standard – a basic blueprint that any university program can use. CubeSats are actually known as "FedEx satellites," since universities can mail them to Cal Poly to arrange a ride into space. They've created launching devices called P-Pods (a box that fits the CubeSats perfectly) so they can piggyback on larger rocket launches. Once the main cargo is deployed, the P-Pod releases the CubeSats into orbit. Depending how high they are, CubeSats can orbit for more than a decade before they burn up in the atmosphere.

What started at universities has spread – NASA, Boeing and other aerospace companies all have mini-satellite programs. Despite the small size, CubeSats are actually able to do valuable research. They can space test new technology, submitting it to all the rigors of space travel like solar radiation and launch stress. Recreating those conditions on the ground can be very expensive.

CubeSats can also gather scientific data. On Tuesday, NASA will be launching Pharmasat, which they hope will be their second nano-satellite in orbit. It will carry yeast samples, and once in orbit will hit them with an anti-fungal to see if their resistance is increased in space. NASA has previously observed that some bacteria are more resistant to antibiotics in space, something that could be dangerous for future human space travel.

You can tune in on Tuesday evening for the Pharmasat launch. Three other CubeSats from Cal Poly and other organizations will also be getting a lift into space.

Listen to the Do-It-Yourself Mini-Satellites radio report online, and see our Web Extra: Mini-Satellites Slideshow.

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Star or Comet?

Remember the solar wind I wrote about a few weeks ago? This stream of protons does more than create comet tails and aurora, it also destroys all of those fancy electronics we work so hard to put into orbit.

The protons streaming from the sun carry a lot of energy, and they leave a lot of this energy behind as they pass through satellites and astronauts that don’t have the Earth’s atmosphere to protect them. The energy released wrecks havoc on the system, throwing electrons and atoms around like a game of ping-pong. This is one form of radiation damage.

Definitely a comet!
This radiation damage is harmless over short periods of time, much like an occasional X-ray at the dentist. However the solar wind becomes a problem for something like the Hubble Space Telescope or our proposed satellite SNAP which are exposed for many years.

To understand how a telescope degrades from exposure to radiation, let me give an extremely quick explanation of how we gather astronomical images. A telescope is very similar to a camera you buy in the store. The large mirror is equivalent to the lens on your camera. The part that suffers the most radiation damage is the Charge Coupled Device, also known as a CCD.

The CCD is essentially the same as the 8-megapixel chip in your digital camera. This serves as an electronic version of film, recording the image through the photoelectric effect rather than through a chemical reaction. If you can still remember how photography was in the days of film, I'm sure you can appreciate the relief of going digital. Astronomers realized this early on and were pioneers in the use of CCDs.

The photons from the subject of the photograph collide with electrons in the silicon of a CCD, knocking them free from their parent atom. The free electrons are then collected in a well near the site of the collision. Once the exposure is complete, charge is moved one well (or pixel) at a time toward a transistor which then reports the number of electrons found. This process is usually described through the analogy of a bucket brigade passing buckets of water from a reservoir to a fire.

When the CCD is brand new, the bucket brigade performs almost perfectly. If I want to observe a star, the image comes out crystal clear. However, after enough time in space and in the solar wind, the CCD begins to show its wear. The bucket brigade gets sloppy at work and has to contend with an increasingly difficult obstacle course, spilling a little bit of water (or electrons) during each transfer. That same star now leaves a trail of charge behind and begins to look more like a comet.

Now, if I am observing a star, I want my image to look like a star, not like a comet. Is that really too much to ask? Unfortunately, the CCD will inevitably deteriorate in space and astronomers have to find ways to predict and correct for this deterioration. This is what we spent yesterday discussing. We passed around some pretty good ideas but still have a bit of work to do before we can prove a new method for correcting the images. I just hope we it figured out before our satellite launches in 2015!

Kyle S. Dawson is engaged in post-doctorate studies of distant supernovae and development of a proposed space-based telescope at Lawrence Berkeley National Laboratory.

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