The week holds a plethora of sky gazing opportunities.
First off, Saturday, September 18th will debut the very first International Observe the Moon Night. The evening is an offshoot of many programs that exist to explore and study Earth’s closest neighbor, including the very successful Lunar Reconnaissance Orbiter which has been sending back detailed images of the lunar surface. The moon will be in its waxing gibbous phase on Saturday, moving from a quarter to a full moon by Thursday, the 23rd of September.
As the moon moves through its phases, there will be a few objects competing for your attention in the night sky. Monday evening, September 20th and Tuesday morning, September 21st, will see Jupiter at its closest proximity to Earth in over 40 years. This will make Jupiter the second brightest object in the night sky after the moon. Jupiter will be visible throughout the evening, appearing almost directly overhead at midnight. As you’re looking for Jupiter you may also be able to see Uranus just above the giant planet. Unlike Jupiter, which is visible to the unaided eye, you’ll need a good pair of binoculars or a telescope to make out the tiny blue green Uranus.
If staying up until midnight isn’t your cup of tea, there’s also the chance for some early morning observations over the next few days with Mercury appearing low in the eastern sky about an hour before sunrise. The best days for viewing Mercury will be September 18, 19, & 20th. While Mercury will look like a pinkish colored light to the naked eye, a telescope may allow you to see the planet pass through a quick change of phases similar to those of our much slower moving moon.
Don’t worry if you don’t have your own telescope, because on Friday, September 24th, The Fort Collins Museum & Discovery Science Center, along with the Astronomy Department of Front Range Community College, will host the Star Nights program at the Stargazer Observatory. The event runs from 8:00 to 10:00 PM on Friday evening and will include the StarLab Planetarium program, access to the telescope at the Stargazer Observatory, and other hands-on activities. The program is offered free to the public, although registration is required due to limited availability. To make a reservation, please contact Toby Swaford at 970-416-2705, extension 2.
Since meteor showers are a favorite of sky watchers worldwide, viewers in North America are in for a treat – weather permitting!- around August 10 – 12th. The annual Perseid (“Purr-see-yid”) Meteor Shower will occur as the earth passes through the remnants of Comet Swift-Tuttle.
Perseid fireball meteor
The Comet Swift-Tuttle
The Perseid meteors got their name because the point in the sky they appear to come from, also known as the radiant, lies within the constellation Perseus. The meteors are the debris in the tail of the comet Swift-Tuttle, which got its name from the two American astronomers who independently (as often happens with comets) discovered it in the 1860s. Swift-Tuttle was later “rediscovered” (as also often happens with comets) in 1992. Historians have traced Swift-Tuttle’s orbit around the sun back nearly 2,000 years, and it’s believed that the comet was observed in 188 A.D. and possibly as early as 69 B.C. Because Swift-Tuttle has a very long orbit, the comet won’t pass close to Earth again soon. However, the pass that will happen in 2126 is predicted to be spectacular, so be sure to have your great-grandchildren mark their calendars!
Swift-Tuttle Path
Viewing the Perseid Meteor Shower
Certain things can interfere with the viewing of meteor showers. Two of the big ones are moonlight and light pollution. The moonlight won’t be an issue during this year’s Perseids; the moon will be new on August 10th and will set soon after sunset for the days of the meteors. However, there’s not much you can do about light pollution except finding a site with suitably “dark skies;” that is, an area far (or as far as possible) from cities, industrial plants, airports, etc.
If you live near Fort Collins, two of the city’s Natural Areas will be hosting meteor shower-watching programs: from 7:45 pm to 11:00 pm on Thursday, August 12th at Bobcat Ridge Natural Area and from 7:45 pm to 11:00 pm on Friday, August 13th at Soapstone Prairie Natural Area. Visit the Natural Area’s website for more details and registration information.
Once you’ve got a dark skies site already picked out, the next step is determining where to look. Locating Perseus isn’t difficult. The constellation isn’t the brightest in our night sky, but it’s located just “below” a bright and distinctive constellation, Cassiopeia (“Cass-ee-O-pea-yah,” or “Cass-ee-o-PAY-yuh,” your choice).
Cassiopeia
Here’s how you find Cassiopeia:
First, locate when and where the sun sets from your viewing location; your local newspaper will have sunset information.
Then, stand with the sunset on your left shoulder. The sun sets in the northwest at this time of year. If northwest is on your left shoulder, then you’re facing northeast.
Establish some landmarks – a tree, etc. – to remind you which way northeast is.
Once it gets sufficiently dark (about an hour after sunset), go outside and face northeast. Cassiopeia will be low in the northeast and rising. Along with the Big Dipper and Orion, Cassiopeia is one of the most easily recognized constellations in the northern hemisphere, for at this time of year it resembles a raggedly-drawn letter “W.” Perseus is just “below” Cassiopeia. Once Cassiopeia has risen so that it’s well over the trees and rooftops, look below it so see a small magician’s-hat shape of stars. That’s the head of Perseus, and the rest of the constellation will follow!
Now comes the hard part – waiting. You won’t need a telescope or binoculars to see the meteors, but you will need some patience. To watch the meteor shower, you’ll need:
A comfortable chair. Preferably one with a place to rest your head.
Bug spray. This won’t be like viewing the Leonid meteor shower in November; the mosquitoes still will be out unless it gets cold, in which case having some sweatshirts or jackets is a good idea.
Patience. You should sit and face the shower’s radiant, the place in the sky where the meteors appear to come from. Facing Cassiopeia is close enough. And then you have to wait: maybe a long time, maybe not. Keep your eyes relaxed – you never know when or where you might see a meteor.
What You’ll Be Seeing
While still in space, the debris from Swift-Tuttle are called meteoroids. These meteoroids are fast, entering the Earth’s atmosphere (at which point we start calling them meteors) at 70 kilometers/second (slightly faster than 45 miles/second). Most of the meteors are the size of a grain of sand, but some can be as big as a marble. Once in the Earth’s atmosphere, the meteors heat up, reaching more than 3,000 degrees Fahrenheit (1,650 degrees Celsius). Most meteors vaporize in the extreme heat, creating what we call shooting stars. Any meteors that do reach the Earth’s surface before being completely burnt up are called meteorites.
While you’re meteor-spotting, treat yourself to some other sights of the night sky. You might have to refer to a constellation chart for these, so it would be wise to do your reviewing before you leave the house.
Using your NW-NE reference, face halfway between those directions and you’ll be facing north. The “Big Dipper,” everybody’s favorite group of stars in the northern hemisphere, will be high in the NW (your upper left) and swinging down towards the horizon.
Our “Home” galaxy, the “Milky Way,” will be passing immediately overhead. If you’ve never seen the Milky Way – and may people haven’t – look for a broad, hazy-looking band, almost looking like a band of faint, thin clouds. If you follow the band down to the south, you’ll be looking directly at the heart and center of the galaxy.
Just above the southern horizon, look for a single, bright reddish-orange star. This will be Antares (“An-TAHR-ayz”), the “Rival of Mars” (which is what Antares means), in the heart of the constellation Scorpio.
If you’re up late enough, the planet Jupiter will be rising in the southeast. Jupiter will appear a creamy white color, and if you’ve got a small telescope or binoculars with you, you might be able to see some of Jupiter’s larger moons, looking like tiny stars on either side of the planet.
Weather and other conditions permitting, here’s wishing you “Good seeing!”
New thermal imagery of Jupiter's Great Red Spot. Photo courtesy of the European Southern Observatory
It was 70 degrees today in Fort Collins, but we’re under a winter storm watch with 5-10″ of snow on the way by Friday. This is otherwise known as “Spring in Colorado.” Here’s another storm that’s just a tad bigger and has been going on for (at least) hundreds of years: the storm at the heart of the Great Red Spot on Jupiter. Check out this report from the European Southern Observatory, which has just obtained some ground-breaking thermal imagery of the largest storm in the solar system: Scientists Get First Look at Weather Inside the Solar System’s Biggest Storm.
Last month we had a look, and hopefully a listen, both to the planets visible in the night sky and to those same planets featured in Gustav Holst’s The Planets. This month, we finish off the night sky and the musical movements (except for Pluto, which wasn’t a planet when Holst composed his piece, and isn’t a planet anymore).
JUPITER, which was visible the last two months, is almost completely swallowed up in the glare of the just-set sun now. The planet is just above the horizon and almost impossible to spot, although on February 16th it appeared to be next to the planet VENUS, a “conjunction,” and the two planets gave the optical illusion of appearing to pass one another while going in opposite directions. While they didn’t literally pass by one another, they are moving in opposite directions across the sky. Jupiter will vanish from our evening skies soon, only to reemerge as a pre-dawn planet later in the spring. Venus, on the other hand, appears to be slowly climbing higher into the sky each night after sunset. As February ends and March begins, Venus will be brighter and higher each night, but it’s still a hard planet to spot.
The movement of The Planets, “Venus, the Bringer of Peace,” is heard immediately after the brutal orchestral roars that conclude “Mars, the Bringer of War.” In complete contrast to the harsh and mechanical sounds of “Mars,” “Venus” is cool, calm, and, above all, peaceful. The subtitle for The Planets is “Suite for Large Orchestra,” and this largeness is demonstrated imaginatively in the opening of “Venus.” Holst wrote parts for extra flutes, more than were usually found in orchestras of the time. Their sound offers a coolness that comes as a relief after the fire, smoke and pain of “Mars.”
The planet MARS is well up in the northeast at sunset, high overhead by midnight, and setting in the west (if you happen to be up before dawn) by night’s end. Look for it now, though, while Mars still is bright. Its brightness will quickly fade during March as the earth’s smaller, swifter orbit pulls away from the planet.
Next to be seen is the planet SATURN. At this time of year, Saturn is passing “through,” or in front of, the constellation Virgo. Virgo is a large constellation, but not as easily spotted as some others like Leo, the Lion (immediately to the right, or west, of Virgo), or Scorpio, the Scorpion (low to the left, or east, and with faint Libra between it and Virgo). Leo and Scorpio have distinctive shapes, especially Scorpio. Virgo…well, it just sort of sprawls above the southern horizon, as seen from the Northern Hemisphere. It is the largest of the Zodiacal constellations and Saturn, a slow mover, will be “in” Virgo for a long time.
Saturn’s most famous feature is its rings. For many years, scientists thought it was the only planet that had rings, but we now know that the three other “gas giants” of our Solar System: Jupiter, Uranus, and Neptune, also have rings. While Saturn’s rings ordinarily make for a spectacular sight, we’re out of luck for the next few years. During each of Saturn’s orbits around the sun (approximately 29.5 of our years), there are times when our view of its rings is edge-on, making them largely disappear from view. Sadly, the rings won’t be really visible for another few years.
These nights, Saturn looks like a golden-colored star in western Virgo, somewhat below the “tail” of Leo. It will rise in the southeast at about 7:30 PM by the end of February, and then will rise progressively earlier each night after that. The difference is hard to notice, but it adds up to a 2-hour change during a month, and by the end of March, Saturn will rise at 5:30 (6:30, Daylight Savings Time, by then).
In The Planets, Saturn is “The Bringer of Old Age.” This title makes sense, for one of the names the ancient peoples gave the planet Saturn was “Chronos,” or Time. Of the visible planets, Saturn is the most distant from the sun and seems to move the slowest of all, taking almost 30 years to make one revolution around the sun.
A quiet and slow musical tick-tock marks the passage of time as the movement “Saturn” opens. The music has almost a heartless and indifferent quality to it as it slowly and steadily counts off “…the Days of Our Lives”, as the announcer for the soap opera used to say. This tick-tock suddenly ends as a slow procession begins in the trombones. Then, the flutes that were so cool and peaceful flutes in “Venus” appear again. It’s hard to imagine any sort of flute sound as being menacing, but that’s exactly what happens here as the flutes slowly and inexorably come closer…and closer. Chimes sounding like a clock striking the hour give something close to a feeling of despair, but the music ends peacefully, with a resignation that nevertheless isn’t devoid of hope.
Finally, the planet MERCURY. Mercury is closest to the sun of all the planets, and so can only been seen from earth for a short time before sunrise or after sunset. Right now, Mercury is too close to the rising sun to be easily spotted, but later in springtime it will be visible briefly above the sunset. We’ll talk more about Mercury in a later blog post.
“Mercury, the Winged Messenger” is the third (and shortest) movement of The Planets. Where “Mars” was relentless and “Venus” placid, “Mercury” is a masterpiece of musical restlessness. The element Mercury often is called “Quicksilver,” and the music matches this quality well: darting, swooping, dancing, and never staying in one place for long. In fact, at one point in the movement, Holst gives the instruction senza misura – “without a measure” – meaning that for a time there is no sense of rhythmic pulse or beat, but just notes scurrying about gaily. A short burst of a quiet chord, almost like seeing distant fireworks, ends the movement.
And that brings an end to this examination of both planets and The Planets. As mentioned before, the music is easily found online and elsewhere, and is one of several works that, for musicians and non-musicians alike, is unforgettable after first being heard. I hope you’ll enjoy both the planets and The Planets.
The beginning of 2010 offers anyone interested in astronomy the opportunity to view several members of our Solar System. At those times when, thanks to snow clouds, the night sky can’t be seen, why not experience the Solar System through the most famous musical depiction of the planets: The Planets, by the English composer with the decidedly non-English name of Gustav Holst.
Your first experience with this music will almost certainly be a memorable one (I’ll never forget the first time I heard it) and, of all of Holst’s works, this is the easiest to find. If your local library has anything by Holst in their “classical” CDs section, they’ll have this. Also, there are many extracts or full-movement performances available on the internet.
The first-time listener to The Planets will find that much of the music, particularly the first and last movements, sound strangely familiar. There’s a good reason for this. Many contemporary composers, particularly those who compose music for movies, have borrowed freely and lavishly from The Planets!
The movements as presented in the The Planets– Suite for Large Orchestra, are “Mars, the Bringer of War,” “Venus, the Bringer of Peace,” “Mercury, the Messenger,” “Jupiter, the Bringer of Jollity” (or Mirth, as it’s sometimes given), “Saturn, the Bringer of Old Age,” “Uranus, the Magician,” and “Neptune, the Mystic.” The planet (or non-planet) Pluto hadn’t yet been discovered in 1914, when Holst began writing the piece. When Pluto was discovered in 1930, Holst chose not to write an eighth movement for The Planets.
The planets we can see this month won’t follow Holst’s performance order. We’ll start with what can be seen just at or after sunset, since things seen then are the earliest to set and vanish, and then work our way eastward, or to the left.
JUPITER is visible this month, and will be for part of February as well. To see Jupiter, first determine where to see the sunset from your location. Go outside maybe half an hour after the sun’s gone down, and face where the sunset was. If you look halfway up the sky and just s-l-i-g-h-t-l-y to the left, you’ll see what looks like a bright, solitary “star.” That “star” is the planet Jupiter, the largest of the planets in our Solar System and the quickest to disappear into the little bit of light still present from the set sun. If you observe Jupiter through a small telescope or binoculars held steadily (using a tripod, or resting your arms on a car roof helps), you might see several tiny star-like points of light lined up on either side of the planet, and if you look again in two or three nights, you’ll see that these lights will have shifted position. The lights are actually several of Jupiter’s moons, named the “Galilean” moons, since the astronomer Galileo was the first to see them and determine what they were.
Holst was inspired by the astrological traditions associated with the various planets as he composed the movements of The Planets. “Jupiter, the Bringer of Jollity” brims with good feeling and merriment, an appropriate portrayal of Jupiter, who was depicted astrologically as rousing and roistering. The contrasting slow section in the middle of the movement has a hymn-like quality to it, and indeed later was used as a hymn in England (rather to Holst’s disapproval), with the words “I Vow to Thee, My Country.”
NEPTUNE is, sadly, never visible to the naked eye and you’ll need a fairly large telescope to see it, but it’s just 2 degrees to the lower right of Jupiter, shifting to the lower left as the month progresses. Even through very powerful telescopes Neptune can be hard to spot, so don’t be disappointed if you can’t see it. Instead, I’ll dare any first-time listener of The Planets to listen to “Neptune, the Mystic,” the movement written about the most mysterious and distant planet known in Holst’s time, in a darkened room. That’s all I’ll say about it, except to invite you to let me know, via the comments section of this post, what you thought if you’re brave enough to try!
URANUS, the farthest planet that can be seen without a telescope, can be found just one constellation to the east (or the left) of Jupiter. It’ll be passing in front of the constellation Pisces, the Fishes, by mid-January. You’ll need a star chart (available at the Museum’s front desk, or check online) to find the “Circlet” portion of faint Pisces, but Uranus will be just below that particular group of stars. If you’ve got 7X50 binoculars, you might be able to see the planet look like a blue-green disc, with the color coming from clouds filled with tiny methane crystals.
“Uranus, the Magician” is one of the funnier moments of The Planets, as the magician of Holst’s imagination is rather something of a bumbler. After a bombastic introduction, the music starts off in a galumphing way. The piece sounds similar to The Sorcerer’s Apprentice by Paul Dukas, the music Disney used for Mickey Mouse and the magic brooms in the film Fantasia. Gustav Holst’s daughter Imogene stated that, to her knowledge, her father never had heard the Dukas work at the time he wrote The Planets, and that might indeed be true, but I’d wager that one piece might well remind you of the other.
MARS is easily seen low in the east after sunset. Distinctly reddish-orange, Mars will be passing in front of the constellation Cancer, the Crab, and will be closest to Earth in its orbit (and therefore, its brightest) on January 29th, the same night that a full moon will appear to be passing the planet. By midnight, Mars will be high in the southern sky, and will have dropped to the westward in the hours before sunrise.
The movement “Mars” opens The Planets, and is remarkable in how brutally repetitive and mechanical-sounding the rhythm that underlies the music is. Holst composed “Mars” just months before the assassination of Archduke Ferdinand of the Austro-Hungarian Empire, the act that led to World War I – what the British called “The Great War.” The mechanical nature of the piece seems to anticipate the mechanized warfare that would soon begin. This is powerful, frightening music.
We’ll look at Venus, Saturn and Mercury in the next posting. In the meantime, I hope that, along with getting outside and seeing the planets of January for yourselves, you’ll have the opportunity to hear the music Gustav Holst is most remembered for, even though paradoxically, he didn’t at all consider it his best work.
The news is buzzing lately with images of an Earth-sized “scar” in the atmosphere of Jupiter that an amateur astronomer from Australia spotted recently. NASA even oriented the Hubble telescope, which underwent repair in May, to take a look even though it’s not slated to be back online quite yet.
Photo credit: NASA, ESA, and H. Hammel (Space Science Institute, Boulder, Colo.), and the Jupiter Impact Team
The massive scar in Jupiter’s clouds was likely caused by an asteroid or comet. Interestingly, that object was probably only about 50 to 100 miles in diameter. The scar is much, much larger than the object that actually made impact. Why is that? The force of the impact of the object against the gas planet caused debris and what scientists call ejecta to shoot away in all directions from the point of impact. Essentially, the speed and direction of an object (or derivation of momentum with respect to time) at impact influences how big crater will be. In the case of a gas giant planet like Jupiter, we see a scar in the atmospheric gases. The greater the force of impact, the greater the field of debris and ejecta will be.
We illustrate this phenomenon here at the Museum in a cool activity we do with our visitors as part of our Virtual Space Community partnership with Space Center Houston. We create a model planetary surface in a pan by layering flour under a thin layer of cocoa powder. By dropping rocks or beads from varying heights into the flour, we can see the size of the debris and ejecta field caused by the impact of our “asteroid” or “comets.” The flour under the cocoa powder shoots out on all directions. We can see it across the surface of our planet and in a “cloud” over our planet.
Our atmosphere protects us from most asteroids and comets because they usually burn up in our atmosphere — but some do make it to the surface. We call them meteorites and they are spherical in shape because of the forces acting on them as they travel through the atmosphere rounds off their uneven surfaces. The Earth’s moon, lacking an atmosphere, has been, and will continue to be, impacted by objects of all shapes and sizes. No atmosphere, no rounding. Some night when the moon is visible, take a pair of binoculars and look for the irregularly shaped scars of asteroids and comets that have hit the moon over many millennia.
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