If I had a dollar for every time someone in casual conversation had called me an astrologer or astrologist (instead of an astronomer), my retirement funding would be a lot more secure. Often, it's an honest mistake, where the speaker really does understand that astronomy is a science and simply isn't sure of the science's proper name. What's much worse is when I run into a "true believer" in astrology, who thinks that our personality, our character, and our destiny is shaped by the arrangement of stars and the position of celestial objects at the moment of our birth.
Some years ago, I wrote an article for Sky & Telescope magazine setting out an astronomer's reaction to astrology. A much revised and updated version is now on-line, thanks to the Astronomical Society of the Pacific. If you have wondered about astrology and what to say to those who believe in it, this short article may assist you. At the very least, you might find it amusing. In it, I also describe a new field for predicting things called "jetology" (where your future is determined by the position of all the jumbo jets at the moment of your birth.) The article is in PDF file format at:http://www.astrosociety.org/astrology.pdf
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It's a dizzying thought, but the solid ground beneath our feet is moving at great speeds through space. For example, our planet turns once a day. Every 24 hours, the place where you live on the surface of the Earth goes in a big circle around the center of our planet. In the San Francisco Bay Area, this motion happens at a speed of about 818 mph. (Children, you can do this without adult supervision, because gravity holds all of us firmly to the Earth's surface.)
Our planet turns around an imaginary stick that goes from the Earth's north pole through its south pole. We call the line of that imaginary stick the Earth's "axis." As our planet turns around its axis, the Sun appears to rise in the East and set in the West and we have day and night. At night, as we turn, we see everything in space slowly turning around us. But we know the Sun during the day and the stars at night are not really turning. They sit in space and mind their own business. The motions we see in the sky hour by hour just reflect the turning of planet Earth. Do you want to see this motion displayed?
On the magnificent photo I have attached to this little posting, you can actually see the turning of the stars (around the still point of the north pole of the sky). Master photographer Phil McGrew captured the turning of the sky above the Golden Gate Bridge. I was so enchanted with this photo, I asked him to give me permission to share it with all of you. You can see more of his photos at his web site: http://www.philmcgrew.com/
The photo is actually made up of more than 180 20-second exposures, skillfully added together. Instead of being a point, each star becomes a curved line as the Earth turns with the camera and photographer attached to it. Astronomers call the curved lines "star trails."
Can you think of other ways that you are moving even while sitting still in your favorite armchair? We'll discuss these other motions in future posts.
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The Silicon Valley Astronomy Lectures, which I have the pleasure of moderating, feature noted scientists giving nontechnical illustrated talks on recent developments in astronomy. I am happy to announce that they are now available on their own YouTube Channel, at:
http://www.youtube.com/SVAstronomyLectures/
The talks include:
* Frank Drake (the father of the search for radio signals from civilizations in space) discussing his modern view of the Drake Equation,
* Michael Brown explaining how his discovery of the dwarf planet Eris led to Pluto being kicked out of the planet club,
* Alex Filippenko (selected as the U.S. Professor of the Year, a few years ago) talking about the latest ideas and observations of black holes,
* Natalie Batalha (mission scientist for the Kepler Project) sharing the latest planet discoveries from outside the solar system, and
* Chris McKay updating the Cassini discoveries about Saturn's moon Titan (the only moon known to have an atmosphere thicker than Earths).
The lectures are taped at Foothill College near San Francisco (where I teach), and co-sponsored by NASA's Ames Research Center, the SETI Institute, and the Astronomical Society of the Pacific.
Note that the top page of the YouTube channel shows the lectures in the order they happened to be uploaded to YouTube. If you want to see them in chronological order, select the Playlist option.
Both new and older talks in the series will be added to the channel as time goes by. Many well-known astronomers have given talks in this series since its founding in 1999; recent lectures are being recorded so that people around the world can "tune in."
(About the picture: This is a false color image of the Helix Nebula, the last gasp of a dying star located about 650 lightyears away. A relatively low-mass star is collapsing and losing its outer layer in a final internal adjustment before it dies as a white dwarf. The material the star loses is excited by the energy of the shrinking star and set to glow. In this image, infrared radiation (as measured from the Spitzer telescope in space) is shown in green and red, ultraviolet radiation (as measured by the GALEX telescope in space) is shown in blue.)
Whenever small chunks of cosmic dust or dirt hit the Earth's atmosphere at high speed and heat up, they make a flash of light that's visible from the ground. We call these meteors or "shooting stars." When the Earth encounters an organized swarm of cosmic material, we call it a meteor shower.
The Perseids (one of our most reliable meteor showers) is best this year the night and morning of Sunday Aug. 11 to Monday Aug. 12, and the night and morning of Monday Aug. 12 to Tuesday Aug. 13th.
Watching for meteors is easiest for most people’s schedules in the evenings (before midnight). However, the meteor display is generally better after midnight (making night owls and early risers happy.)
The Perseids are better after midnight for two reasons this year:
a. The Earth turns after midnight to face the shower (so that the meteors are coming more directly at us)
b. The crescent Moon will set by then, so its light will not bother meteor shower fans. (On Aug. 11, the Moon sets at 10:32 pm, while on Aug. 12th the Moon sets at 11:10 pm.)
Whenever during those two nights you decide you want to watch, here are Fraknoi’s Friendly Meteor Shower Tips for best viewing:
1. It’s more important to decide WHERE to watch them, than WHEN to watch them. The crucial issue is that meteors are faint, so you need a location where the sky is DARK. That means getting away from city and car lights as much as possible. The darker your site, the more you will see.
2. Of course, if it’s foggy or cloudy, you won’t see a thing. So make sure you get to a place where the sky is not only dark but CLEAR.
3. Don’t use a telescope or binoculars. (Meteor showers are one of the most democratic of sky shows; those of us in the 99% can enjoy them as much as those in the 1%!).) Your eyes are the best tool, because the flash can be anywhere in the sky. So restricting your view to a small part of the sky makes it more likely you will miss many of the meteor flashes.
4. Dress warm for night-time temperatures and be patient. Meteor showers are far more subtle than fireworks. You will need to relax and wait for time to pass. First, it takes a while for your eyes to get adapted to the dark (I recommend at least 15 minutes) and, second, a minute or several minutes might pass without a single flash. Eventually, though, you should see significantly more shooting stars than on a regular night.
5. So (perhaps most important) try to take someone with you with whom you like to spend time in the dark.
The Perseid meteors are cosmic “garbage” (dust and dirt clumps) left over from a regularly returning comet, called Swift-Tuttle (after the two astronomers who first discovered it). When comets get near the Sun, their ice evaporates, leaving behind some of the dirt that was frozen inside them. Since comets are "left-overs" from the early days of our solar system, you can tell yourself that each flash you see is the “last gasp” of cosmic material that formed about 5 billion years ago.
(Our photo, by ESO Photo Ambassador Stéphane Guisard, shows a bright Perseid meteor in 2010 over the grouping called the Very Large Telescope at the European Southern Observatory in Chile.)
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Every once in a while, I see a new astronomical picture that leaves me with my mouth open, saying "Wow!" The above image, assembled by a talented amateur astronomer, from information taken by a number of different telescopes, is one of those.
This wide-angle view is centered on a cluster of recently-born stars that is known by its catalog number of NGC 2264. Surrounding the adolescent stars is a whole region of cosmic gas and dust -- the raw material from which stars are born. The nearby gas glows with the characteristic red color of its most common constituent -- hydrogen.
At left center is the Cone Nebula, a region of gas and dust in the shape of a sideways dark cone; the energy of bright stars to the right of the cone is eating away at the sides of this thick dusty region, leaving only a cone of thicker material behind.
To the right of the Cone Nebula, you can see an opposite (larger) cone pattern of bright stars stretching rightward. Some people see the lights of a sideways holiday tree in the pattern of bright stars.
At the bottom center of the image, pointing upward into the bluish emptier region (where the energy of freshly made stars is clearing things out), you can see an odd region of gas and dust that is sometimes called "The Fox Fur Nebula." Click on the picture and take a good look -- can you see the head of a furry red fox pointing upward into the bluish region?
The entire complex of stars and gas and dust is about 2,600 lightyears away, which means the light we see tonight left this region about 2,600 years ago -- a time when humans on Earth lived a much more challenging existence and lifespans were less than half of what we enjoy today.
This remarkable picture was assembled by Dr. Robert Gendler, a physician and amateur astronomer, who is a master at working with photographic information using his computer. The image was constructed from information provided by the Subaru Telescope in Japan and the Digitized Sky Survey, put together by astronomers at the Space Telescope Science Institute from a number of earlier surveys of the sky. To see more information about the photo, see:
http://www.robgendlerastropics.com/Cone-Subaru-DSS.html
You can go to Dr. Gendler's home page at that site and then browse his many other wonderful images. But take a minute and just enjoy a full-screen version of the picture -- you are seeing the same process of star birth that gave rise to our Sun some five billion years ago.
An international team of astronomers has found a new kind of astronomical event in the universe -- a powerful flash of radio waves, lasting only a few thousandth of a second, but coming from vast distances away.
Radio waves -- the same kind of invisible "wireless waves" that bring news of traffic jams to our car radios or wifi for our laptop computers -- come from a variety of natural events in the cosmos. If your car radio were to convert them to sound waves, they would sound like static. Radio static comes to us from the magnetic regions of the Sun and Jupiter, from remnants of exploded stars, and many other sources in the sky. But the "transmissions" usually last a long time.
A sudden burst of such waves lasting only a few thousandth of a second (and then never again) came as a surprise to astronomers. The first of these was discovered six years ago, but was classified as doubtful until others could be found. Now astronomers have found a total of five from different directions in the sky. Indications are that they come from far away -- from far beyond our Milky Way Galaxy. If so, and we can still detect them from Earth, they must be very strong bursts indeed. (In the same way, if you scan the horizon and see a flash of light from a distant city, whatever made the light must be quite bright to cross the space between cities and still be visible to your eyes.)
What could make such brief, super-strong bursts of radio waves? It must be something small and powerful. First candidates include the collapsed corpses of stars that are called neutron stars. These are what remains of stars that exploded long ago, and they can pack more than a Sun's worth of material into a ball no bigger than a suburban town (about 20 miles across!) When such densely packed star corpses collapse further or have a magnetic hiccup, they can give off a quick shot of radio energy.
But at this point, no one really knows what sorts of cosmic objects the radio bursts come from and we are eagerly searching for more. This situation is very similar to what happened in 1967 with another kind of invisible wave, called gamma rays. A secret spy satellite found a few bursts of gamma rays coming from space. At first, no one could figure our what they were and why we saw them randomly around the sky. But as decades passed, and we detected more and more of them, with better and better instruments, we learned a lot more about them and began to come up with really good explanations for these "gamma-ray bursts." We may be at the beginning of a similar era of further exploration and gradual explanation with these radio bursts. As they say on the radio, "stay tuned."
(The artistic image with this post shows the radio telescope in Australia that found the new bursts, together with a blue dot symbolizing the (invisible) burst, some distance away from a map of radio waves coming from our own Milky Way, shown with reddish colors. So only the color of the telescope is real, the other colors try to show things our eyes cannot see, using colors we can see. But how else can we have a nice picture with the story?)
I just got back from a fascinating conference in New York on how astronomy has inspired other fields, like art, architecture, poetry, and music over the years. I was the after-dinner entertainmen...I mean...the banquet speaker and had a chance to share the results of my 30-plus years of collecting examples of astronomical music (assembled with the help of many generations of students).
Composers of both classical and popular music have long been inspired by the ideas and discoveries of astronomy. The picture with this post, for example, shows some sheet music from 1901 that was inspired by physicist (and inventor) Nikola Tesla's claim that his early radio equipment had intercepted signals from our neighbor planet Mars. Actually they turned out to be perfectly natural radio waves from the upper layers of the Earth atmosphere, but for a while the news media were touting the idea that martians might be signaling us.
If you want to see my full list of 133 "astronomy music" pieces that you can find on CD, it's at:http://aer.aas.org/resource/1/aerscz/v11/i1/p010303_s1?view=fulltext
With the growth of videos on YouTube and other web sites, you can actually watch some of these pieces being performed. Among my popular-music favorites on video are:
1) "Walking on the Moon" by the Police (comparing the feeling of being in love to being on the Moon's surface):http://www.youtube.com/watch?v=gPpvHEsC_PM
2) "Hawking" by Todd Rundgren (which tries to put the listener in the body and mind of brilliant but wheelchair-bound physicist Stephen Hawking): http://www.youtube.com/watch?v=jk7uZO1iED8
3) "Why the Sun Really Shines" by They Might Be Giants (a children's song): http://www.youtube.com/watch?v=u-KyciKHw-g
4) And, for a change of pace, the "Elements" song by 1960's humorist (and math professor) Tom Lehrer:http://www.youtube.com/watch?v=AcS3NOQnsQM
A number of brave composers have put together musical pieces that are based on the rhythms or tones of actual astronomical observations. There is music based on radio signals from galaxies, on the index of how the Sun affects the Earth's magnetic field, and on the speed with which the planets orbit the Sun. A fun recent example is "Supernova Sonata" -- music based on a catalog of newly discovered exploding stars in other galaxies:http://vimeo.com/23927216
I have enjoyed collecting these musical examples of the power of astronomy to affect our imaginations and hope you enjoy hearing some of them.
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