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.)
Sunday, November 29, 2009
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.
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.
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.
Monday, October 12, 2009
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
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
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