Sunday, November 29, 2009

What If the Earth Had Rings?

Very cool simulation! If the frame is cut off, you may want to click on the video and view it directly in YouTube.



(Hat tip: Michael D.)

Wednesday, November 25, 2009

Time-Lapse of Leonid Meteor Shower 2009

Video by Dave Kodama, Orange County Astronomers.

Given that this video was taken from very dark skies, it is evident what I meant earlier when I said that the term "shower" is a bit of a misnomer. Definitely note that the streaks which can be seen early in the video are from airplanes. Meteors are visible later in the evening after the constellation Leo begins to rise, about halfway through the video.

Sunday, November 15, 2009

Go Watch the Meteors... Maybe


If you've heard the hype about this year's Leonid meteor shower (the Leonids are the annual shower that occurs in November), you might wonder why I've been reluctant to add my voice to the chorus imploring you to go watch it.

That's because meteor showers are total crapshoots. It's definitely not a terrible idea to set your alarm and spend at least a few minutes during the wee hours Tuesday morning, but with some caveats in mind:

First of all, if you haven't ever seen a meteor (or "shooting star"), there are almost zero qualifications to heed. You absolutely owe it to yourself to see one at some point, so consider going outside early Tuesday morning, provided it's clear, and keep your eyes on the sky for 10 minutes or so. You'll see at least one. Especially if you go somewhere fairly dark, i.e. somewhere where you can at least see some of the constellations.

But...

For all but a very few meteor events, I think the term "shower" is a bit of a drunk metaphor. On any given night, there are always meteors; the average is about 2 per hour, or so I've heard. This is because there are just that many random rocks (albeit very small: most meteors that we observe are only sand-grained sized, if you can believe it!) floating around the vicinity of Earth's orbit.

A so-called meteor 'shower' occurs when the Earth passes through an entire debris field of small bits of rock left by comets which have passed nearby in recent years. It may surprise you to learn that these events happen about once every month or so, and this is when the number per hour greatly increases: anywhere from 20 to 50 to 100, or, in this year's most optimistic estimate for November's shower, possibly as many as 300 per hour. Mind you that would mean seeing a shooting star about once every 12 seconds, rather than once every 30 minutes.

(I recommend the following articles for further information: Will the Leonids Roar Again? and The 2009 Leonids Are Coming!)

If that turns out being the case, it may be a really neat thing to watch. Definitely beats having to spend an entire hour outside to see one or two!

But something tells me that if when you go to bathe tomorrow morning, your water were to release a drop from the spigot once every 12 seconds, you wouldn't call that a "shower". So keep your expectations realistic!

This event, in 1833, in my judgment would have been more properly called a shower:

Sunday, October 25, 2009

Nothing Amazing, Nothing Rare...


But it is neat: On Monday evening, October 26, 2009, Jupiter and the Moon will be a mere 3ยบ apart (less than the size of your fist, at arm's length). Above: The view Monday night as predicted by Stellarium; click to enlarge.

Jupiter is currently the brightest object in our evening skies, but if you've not seen this planet with your own eyes, Monday evening presents you with perhaps the easiest opportunity ever to find it.

If you own a pair of binoculars or a small telescope, use them! The Moon looks spectacular with even the smallest optical aid, and often even small binoculars can allow you to detect Jupiter's four largest moons: the scene will appear as a bright "star" (Jupiter) surrounded by four tiny "stars" (Jupiter's four largest moons). The image below, taken by Mathew Wedel at 10 Minute Astronomy, gives you some idea:


On that note, it was exactly 400 years ago November that Galileo became the first human being to point a telescope at the sky and discovered the existence of those moons--and the existence of any object going around something other than the Earth! This represented the first direct evidence in support of the heliocentric theory of the solar system, and further fueled Galileo to uncover fundamental new truths about the nature of motion, laying the groundwork for the modern branch of science known as physics. Pretty pregnant observation, that.

Above: Galileo's own notes recording the relative positions of Jupiter's satellites over the course several days.

Big Sunspot Emerges

It's not much, but a sunspot has emerged which may become the biggest sunspot of 2009. Here's a video, taken using a special filter which blocks out the harmful rays of the Sun. (Source: SpaceWeather.com)



Here's a reminder never to look directly at the Sun, as doing so is dangerous and can lead to blindness. If you own solar eclipse glasses and you've taken good care of them (ensuring they have no holes or scratches), then it may be possible to see this sunspot. Another option is to look for the sunspot when the Sun's light is greatly diminished, as at sunset. However, as of this writing, the sunspot is very small and probably not visible to the eyes alone.

Sunspots usually appear in cycles of every 11 years. The last sunspot "storm", or maximum, was 2001, and we reached minimum in 2006. That means that sunspots should be starting to occur more frequently, as the next maximum is predicted to occur in 2012. This cycle has had an especially low minimum, so scientists are speculating that perhaps we won't have as many sunspots. (Famously, there was a period from 1645 to 1715 when the Sun produced very few sunspots, and some wonder if this may happen again!)

UPDATE: On Sunday afternoon (10/25/09) I attempted to see the sunspot using solar eclipse glasses (which are specially designed for safe viewing of the Sun) but could not see it. So at least for now, it's too small to be seen without special equipment.

Wednesday, October 7, 2009

Rocket and Spacecraft to Crash into Moon on October 9, 2009!

On Friday morning at around 4:30AM (Pacific Time), a rocket and spacecraft are planned to crash into the South Pole of the Moon. Both are unmanned.

Because the Moon has such little gravity and almost no atmosphere (which would help to keep it insulated from extreme heat or cold), the sunlight causes the daytime side of the Moon to be blazing hot: about 250°F, and therefore any water that might have existed would have long ago evaporated towards outer space. (The astronauts who landed on the Moon, for example, found only rocks--mostly basalt, and anorthosite, a rock similar to granite).

But in the 1990s, NASA's unmanned (remote-controlled) Clementine spacecraft discovered that the lunar South Pole contains a region of the Moon that never receives sunlight. Using a special instrument on board Clementine, scientists took a series of special photographs that help to reveal the chemicals of the object being photographed. The photographs of the Moon's South Pole seemed to suggest the presence of water, although scientists were not able to tell for certain.

Above: One of Clementine's (normal) photographs of the Moon's South Pole.

If water were found to exist on the Moon, that would be very useful to know. Water is relatively heavy and therefore expensive to transport into space. The presence of water on the Moon could make it cheaper to one day establish a permanent human settlement on the Moon. Water can also be used to create hydrogen, the main component of rocket fuel.

After the Clementine mission in the 1990s, eventually NASA planned future missions to follow up on this "lunar South Pole" discovery. The LRO (Lunar Reconnaissance Orbiter) spacecraft, launched this year, has made the most detailed maps of the Moon yet, identifying future safe landing sites and radiation levels. (Its cameras are so good that it's even been able to take photographs of the landing sites and leftover equipment from the Apollo astronauts, which you can see in the image below; you can read more here).


Another spacecraft, part of the LCROSS mission ("Lunar CRater Observation and Sensing Satellite"), has now finished taking even more chemical photographs of the Moon from space, and on this Friday will achieve its grand finale: firing a rocket toward the Moon's South Pole, followed by then crashing itself into the South Pole.

Above: LCROSS being launched into space on June 18, 2009.

Because of the Moon's low gravity, these collisions should cause debris to be ejected into space, which will allow both LCROSS (at least at first collision), LRO, and observers on Earth to use the same special type of camera to get an even more detailed view of the chemicals present.

Above: The LCROSS spacecraft being prepared to be loaded into a rocket, May 2009.

Will we find water? You'll have to wait and see! Photos and hopefully a video from the collisions will be posted here on this blog sometime next week.

Check back!

PS: Although the collisions can be observed from Earth, they are only visible using a telescope that is 10" or larger in diameter. It will be broadcast live on NASA TV (if you have access to that), although if you prefer to sleep at 4:30AM, you can always watch recorded coverage on the news, or check back on this blog in about a week. :)

More info: http://www.nasa.gov/mission_pages/LCROSS/main/index.html

Sunday, September 27, 2009

Rare Space Object Discovered by High Schooler


Read the full story here: http://www.space.com/scienceastronomy/080925-student-discovery.html

(Hat tip: Jimmy Wales)

Seeing in the Dark

Here's another old post (from September 2007), resuscitated. But I know this was a worthwhile book, and the documentary looks equally worthwhile. Reported at the time by the SF Sidewalk Astronomers:

"Stargazing is the subject of Seeing in the Dark, a 60-minute, state-of-the-art, high-definition (HDTV) documentary by Timothy Ferris that [premiered in 2007] on PBS.... (story continued below)



The film, Ferris's third, is based on his book, _Seeing in the Dark_ (2002), named by the New York Times as one of the 10 best books of the year.

Seeing in the Dark will bring the wonders of the night sky in state-of-the-art HDTV to millions of viewers. The program features remarkable high-definition astrophotography, as well as the men and women, professionals and amateurs, who have seen and captured phenomenal images within and beyond our solar system and galaxy. It also explores how inexpensive telescopes, sensitive digital cameras, and the Internet now enable casual stargazers to get in touch with the cosmos.

Like the book, the film is in part a personal account of Ferris' life-long devotion to stargazing, beginning with his introduction to the night sky as teenager in Florida in the '50s.

'Seeing in the Dark is meant to alter, inspire and illuminate the lives of millions,' said Ferris. 'It introduces viewers to the rewards of first-person, hands-on astronomy--from kids learning the constellations to amateur astronomers doing professional-grade research in discovering planets and exploding stars. I hope it will encourage many viewers to make casual stargazing part of their lives, and a few to get into serious amateur astronomy.' "

Via Matthew Ota, Orange County Astronomers mailing list.

Wednesday, September 16, 2009

Sunday, May 24, 2009

New Horizons

(Note: This is a post dated February 2007, from an earlier version of this blog.)

On February 28, 2007, the New Horizons spacecraft reached Jupiter orbit, and took the below photograph.

For those unfamiliar with this spacecraft, New Horizons is destined for Pluto and the other small, icy worlds beyond the orbit of Neptune. Neither Pluto nor these worlds have been photographed before, so there is something particularly significant about this mission: it truly represents the final frontier in this, our Age of Exploration of our solar system.

(Uranus and Neptune were studied by NASA's Voyager missions of the 1980s; Jupiter and Saturn have been visited even more times--with the Cassini spacecraft presently giving Saturn the most in-depth look we have ever obtained of that planet; don't miss the stunning photographs in December 2006's National Geographic).

As if this weren't exhilarating enough, New Horizons is also the fastest spacecraft ever launched. Upon its launch last year on January 17, it passed the orbit of the Moon in just nine hours. Nine hours! If that doesn't mean anything to you, consider that the Moon is 239,000 miles away from the Earth, and that it took the Apollo astronauts of the 1960s and 70s a full three days to reach it.

So, New Horizons has now arrived at Jupiter, a planet which at this particular moment happens to be a waystation along the path to Pluto. It will circle Jupiter just once, using the planet's immense gravity as a slingshot to give it one last boost off to its end goal. How fast is New Horizons travelling?

33,000 mph!

Even travelling at such great speed, it won't arrive at Pluto until... 2015. That tells you something about how far away Pluto is.

....

I think of my parents as having grown up at the dawn of the Space Age, and therefore having had the great fortune of watching its pinnacle with the Apollo missions of 1963-1972. But what many of us don't realize is that my generation has been growing up in a veritable Second Space Age. Those who have been willing to look, have been witness to the first in-depth exploration of Venus, Jupiter, Saturn, Uranus, and Neptune. And this is to say nothing of the astounding achievements of our great space telescopes--especially Hubble--which for nearly two decades now have been making entirely unprecedented observations of stars, galaxies, and a plethora of celestial oddities from quasars to black holes. (The Hubble Heritage Project, since 1998, has been working to keep the public informed of the most awe-inspiring of these discoveries each month).

It is said that for the last Apollo mission, just three years after the first landing, the television networks did not even carry live coverage of the event (in fact the remaining missions had already been scrapped by the government for lack of popular support).

Far, far too many today make the same mistake of our fathers, who were, at best, blind to the achievement (and at worst, numb to it).

Let us resolve not be among these blind.

Saturday, February 28, 2009

My (Lack of) Opinion About Pluto--and Its Implications for My Career


Last Friday I posted about Illinois' state legislature passing a resolution to reject the "demotion" of Pluto to the status of 'minor' planet.

This is a subject that I sensed had been on the periphery of the news for three or four years now, and seemed to me that it had been more the punchline of a cute "throw-away" joke of a late-night talk show host than a serious issue, which is why I speculated the Illinois resolution might be tongue-in-cheek. I was surprised--and even happy--in finding that this issue is evidently contentious among some laypeople and science enthusiasts, as I witnessed from the commenter on my last post, Laurel.

As someone who writes science curriculum, I'm delighted to see this kind of discussion, because it's not often I get to see serious headlines discussing some of the daily issues with which I grapple.

That said, in my comment on my last post, I expressed my view that Pluto's status is a "relatively pedantic issue". Let me briefly outline three reasons why I think this is so.

(Image source: Wikimedia Commons)

1. Over the course of the last ten years, astronomers have been continually discovering small, icy, Pluto-like bodies in the realm of the solar system beyond the orbit of Neptune. They've dubbed this region "the Kuiper Belt" (for astronomer Gerard Kuiper), and most interestingly, one of these objects--Eris--is even larger than Pluto itself. A few of these objects are near Pluto-size, however slightly smaller. The parallels to the "Asteroid Belt", or realm of small rocky objects between the orbits of Mars and Jupiter, are obvious.

2. The issue is not about whether Pluto will be mentioned in schools. Claims to the contrary are misleading, as no one is questioning Pluto's status as a planet, rather its status as a major planet. The issue is simply that Pluto is obviously not anything exceptional beyond being one of several prominent members of the Kuiper Belt. The issue affects 3rd grade playground chalk drawings and clothing-hanger mobiles like this: M, V, E, M, Asteroid Belt, J, S, U, N, Kuiper Belt.

So why mention Pluto at the expense of other Kuiper Belt objects? I'm all for fairness... why not mention Eris and Sedna too? All of these objects have interesting stories behind their discovery and their inferred characteristics, stories that help bring the "Kuiper Belt" to life. (For the Asteroid Belt, that means mentioning one or two of the larger asteroids, too, like Ceres or Vesta.)

3. There are profoundly important, more obviously non-pedantic issues in science education which are in real, desperate, crucial need of public outcry. One obvious contender is the masquerading of creationism as something other than the religious doctrine it is, and the thoroughly dishonest equivocations of its proponents that evolution is "just a theory".

But I'll give you an even lesser known controversy in science education, and one I think even more deserving of your outcry: the divorce of science education from inductive reasoning, (reasoning that starts with the real world out there)--the method by which we reach scientific truths in the first place. The teaching of the planets makes an excellent case in point. How are we taught about the planets in school? We are given diagrams or lists. From these we make planet mobiles in third grade, and we memorize acronyms like "My Very Educated Mother...". But if we had to define the planets from the bottom up--I mean, according to the realm of our own personal, perceptual experience of the world around us--how many of us know for ourselves that planets appear as star-like dots of light above our heads, which wander against the general motion of background constellations known as the Zodiac? If we are even aware of the fact that the planets are accessible to our own naked eyes, how many of us know that these are only some of the planets, and that the discovery of other planets had to wait for the invention and refinement of the telescope? How many of us have even looked through a telescope and seen for ourselves Saturn's rings, and reflected upon the fact that this extraordinary wonder of our Universe has been routinely passing over our backyard for so many years of our lives?

Few if any people do know or experience these things. That students emerge from their science education with a better knowledge of diagrams and memorization schemes than with actual familiarity and true understanding of the real world around them, is an indictment of modern science education and what I would characterize as the "Platonic" intellectual vanguard which has long dominated the education colleges. (And, of course, we all know that the sad reality is that most students instead give up on science, citing it as "too abstract", "boring", and "too much memorization". Is there any wonder why?)

In my own work, I reject this, and in my career I hope to attempt to turn the longstanding tide to the other direction. I'm part of a small minority that thinks that education in science should respect a person's own actual body of experiences, enlarging upon it in a systematic way, and then building upon that. At this early stage, it's an overstatement to even call this a movement--we're extremely small as yet. But we do exist, and if you're interested in science, I hope you will hear more from our school of thought in the coming decades.

Friday, February 27, 2009

Illinois Government Worships God of the Underworld

And that's fitting... because Illinois state government keeps sinking to lower and lower rungs of the Underworld:

The lllinois State Senate passed a resolution to reestablish Pluto's "full planetary status" and declare an official "Pluto Day".

The full text can be found here. Although it appears it might be tongue-in-cheek, I've heard a rumor suggesting that this may have been serious legislation intended to save state money on science textbook revisions. (I can't substantiate that.)

So the State Senate is either assuming the role of satirical humor outlet, or a scientific assembly. Either way, a sound function of government by any rational standard!

I note that the resolution reads ambiguously: "... that as Pluto passes through Illinois' night skies, that it be reestablished with full planetary status". Should we assume they mean that Pluto is only a planet as it passes through Illinois' night skies?

At this point, I don't think it's unfair to assume that of them.