Go Stargazing! June Edition

Saturn
Creative Commons License photo credit: Elsie esq.

Saturn is the only planet visable to us at night this June.  Face south at dusk, and you’ll see Saturn near a star of similar brightness — Spica in Virgo.  Saturn is significantly higher in the sky than Spica and a bit to its right as you face south.   The ringed planet is now well placed for evening viewing, and remains in the evening sky until late September 2011.

Mars and Jupiter are now higher in the pre-dawn sky.  Jupiter, set against a background of very dim stars, dominates the eastern sky at dawn.  Mars is dimmer and much lower in the east northeast.  It has fully emerged from the sun’s glare, however, and will brighten slightly each morning.  Venus does not rise until morning twilight.  Look for it very low in the east northeast as day breaks.

The Big Dipper is above the North Star, with its handle pointing up.  From that handle, you can “arc to Arcturus” and then “speed on to Spica;” those stars are in the south at dusk.  Leo the Lion, is high in the west at dusk.

Antares, brightest star of Scorpius, the Scorpion, is in the southeast, with the ‘teapot’ of Sagittarius rising behind it.  The Summer Triangle has fully risen in the northeast.  The stars of summer are here. 

Moon Phases in June 2011:

New Moon                    June 1, 4:02 p.m.

1st Quarter                  June 8, 9:09 p.m. 

Full Moon                     June 15, 3:12 p.m.

Last Quarter               June 23, 6:48 a.m.

Red Light...
Sunset
Creative Commons License photo credit: Kıvanç Niş

The full moon of June 15 passes through the Earth’s shadow, causing a total eclipse of the Moon. Unfortunately, we miss out on that one, too, as the eclipse occurs during our daylight hours.  Anyone in the Eastern Hemisphere, though, can observe a central (and therefore especially long) total eclipse of the moon. 

At 12:17 p.m. on Tuesday, June 21, the sun is directly overhead at the Tropic of Cancer, the farthest point north where this is possible.  This makes the midday sun as high in our sky as possible and gives us more daylight than on any other day of the year.  This moment is, therefore, the summer solstice.  However, the earliest sunrise for us is the morning of June 11 and the latest sunset is on June 30.  Those of us who sleep through sunrise and witness sunset may get the impression that the days are lengthening all the way to the end of the month.

By popular demand, our George Observatory will open to the public not only on Saturdays, but also all Friday nights in June and July (except July 8).  The Discovery Dome, our traveling planetarium, will be set up each of these Fridays to show films throughout the evening.

Chak Ek’

Page 49 of the Dresden Codex

Have you had a chance to come out and see our newest planetarium show, 2012:Mayan Prophecies?  If so, you’ve enjoyed a fascinating glimpse into an ancient culture known for its astronomy.

The Dresden Codex

Consider, for example, the Dresden Codex, the oldest book known to be written in the Americas.  The best preserved of four ancient Maya writings, this 11th or 12th century document found its way to an owner in Vienna; Johann Götze of the Royal Library at Dresden bought it in from that person in 1739.  (The writing was probably first sent into Europe by Hernán Cortés, conquistador of Mexico.)

The Dresden Codex features tables of eclipses, full and new moons, as well as the times of solstices and equinoxes.  Conjunctions (close alignments of planets in the sky) are noted, as are the times when each planet rises just before or just after the sun.  The Codex devotes six pages to measurements of the positions of Venus.

Chak Ek’

The emphasis on Venus, or Chak Ek’ to the Maya, distinguishes ancient Maya astronomy from that practiced by other ancient cultures.  Of course, people in civilisations all over the world noticed Venus, which outshines everything in the sky except the sun and the moon.  However, other cultures did not consider cycles of Venus as important for time keeping. Let’s look at how Maya astronomers could use Venus as a marker of time.

First, some basic facts about Venus and its orbit.

Venus is the second planet from the sun; Earth is the third. As result, Venus’ orbit is completely inside Earth’s and we see the whole orbit in ‘front’ of us, so to speak. As of May 2011, Venus is in the morning sky, where it has been since November 2010. This means that for the past six months, Venus has been ahead of us on its faster, inner, orbit.

However, we’ll soon see Venus pass around the far side of the sun, making it invisible to us for about a month and a half this summer.  By fall 2011, Venus will have emerged from behind the sun, such that it appears to the sun’s left in our sky.  This makes Venus an evening star, appearing over the western horizon at dusk.  Venus remains an evening star through spring 2012, while it gradually catches back up to Earth, coming back around to our side of the sun. On June 5, 2012, Venus catches back up to us and ‘laps’ the Earth on its faster orbit.  Thus we’ll see Venus quickly drop out of the evening sky in late May and reappear in the morning sky by mid-June.  Venus then remains in the morning sky until it heads around the far side of the sun by March 2013, and the process repeats.

Global radar view of Venus.
Photo taken by NASA

A Venus Cycle

One Venus cycle, as described above, takes 584 days.  Also, as it turns out, Venus completes 13 orbits around the sun in almost exactly eight years.  On a given date in 2011, for example, Venus is where it was in the sky on the same date in 2003, within two days.  These facts enabled the Maya to keep a regular calendar of Venus’ appearances.  For the Maya, each Venus cycle began with Venus’ entry into morning sky, rising just before the sun.  Called the heliacal rising of Venus, this is the moment when Venus is on our side of the sun, having just ‘lapped’ Earth and pulled ahead on its faster orbit.

Maya astronomers also noted Venus’ emergence into the evening sky, but considered that less significant.  After all, Venus becomes an evening star only gradually, taking over a month to emerge from the sun’s glare.  It is also dimmer than average at this time because it is on the far side of the sun from us.  On the other hand, Venus enters the morning sky quite quickly and dramatically, appearing noticeably higher each morning for several days.  And since Venus is closest to us at that time, it is also brighter than average.  Upon observing a heliacal rising, Maya astronomers knew the next would occur 584 days later.  And they knew to expect another such rising of Venus during the same season about eight years later.

The Only Planet Named for a Goddess

Due to its brillance, cultures around the Mediterranean associated Venus with love and beauty.  That’s why Venus is the only planet named after a goddess.  At one time, the Greeks distinguished the evening star Hesperus (Latin ‘Vesper’) from the morning star Phosphorus (Latin ‘Lucifer’), but they were both names for Venus.

Maya also distinguished the evening star (Lamat) from the morning star (Ah-Chicum-Ek’).  For the Maya, either appearance of Venus was a harbinger of evil–particularly the morning star.  This made Venus’ sudden appearance at dawn a good omen for someone wishing to wreak destruction.  Accordingly, Maya often scheduled attacks on rival cities to coincide with the heliacal rising of Venus.  One such attack, which the Maya called a ‘Star War,’ is depicted in our show.

Looking For Venus Today

If you want to observe Venus today (May 2011), you need to rise before dawn and face east.  An interesting gathering of four planets, in progress for much of the month, still continues.  As I write this, Venus and Mercury have passed Jupiter and are approaching Mars.  Venus and Jupiter are about eight degrees apart with Venus to the lower left.  They far outshine everything else but the sun and the moon, so those two planets are easily noticeable well into twilight.  Mars and Mercury appear to either side of Venus  and are much dimmer.  Right now, Mercury is to the lower right of Venus with Mars to the right and a bit above Venus. Today, Venus is within one degree of Mars.  Mars is above Venus, Mercury below.  The alignment of Mercury, Venus, and Mars was closest on the morning of May 21.

After this, Mercury quickly exits the scene while Venus gets lower and lower in the pre-dawn sky throughout June, until it is lost inthe sun’s glare by July.  2012, however, offers some spectacular views of Venus.  In spring 2012, Venus appears as high as possible in the evening sky (as it did in 2004 and will do again in 2020). That particular evening apparirion ends June 5, 2012, as Venus aligns so well with the Earth and sun that it appears as a dot on the sun’s disk.  That transit of Venus will be the last such event in the lifetime of anyone alive today.

Hopefully, none of this will be taken as a sign to sacrifice or invade others.

What do you know about 2012? [Quiz]

To celebrate our new Planetarium Show 2012: Mayan Prophecies, we are testing your knowledge of the significant Maya date of December 21, 2012. How much do you know about this important day?

Are these statements TRUE or FALSE?

1. Dec. 21, 2012 marks the end of the longest Mayan time cycle.

2. The Aztecs knew about 2012.

3. In 2012, solar storms will burn the surface of the Earth.

4. Dec 21, 2012 is a significant celestial date.

5. The Maya used the 26,000-year precession cycle to predict events in 2012.

6. There will be a cataclysmic event in 2012.

7. An impending pole shift will tear the Earth apart in 2012.

8. There is a special alignment of the sun in front of the Milky Way galaxy on Dec. 21, 2012.

9. A rogue planet, such as Nibiru or Eris or Planet X, is going to destroy the Earth in 2012.

10. A geomagnetic reversal in 2012 will devastate the planet.

11. A “global awakening” is coming in 2012, leading to a societal transformation.

12. The Earth will pass through the Galactic plane.

2012: Mayan Prophecies
A scene from 2012: Mayan Prophecies, Now Showing in the HMNS Planetarium!

ANSWERS:

1. Dec. 21, 2012 marks the end of the longest Mayan time cycle.
TRUE: Dec. 21, 2012 is the beginning of the 13th Baktun in the Maya Long Count. This is a day of celebration, much like Jan. 1, 2000 was for us.

2. The Aztecs knew about 2012.
FALSE: There is no archeological evidence that 2012 was significant to any other MesoAmerican civilization.

3. In 2012, solar storms will burn the surface of the Earth.
FALSE: A massive solar storm could take out a satellite, but cannot reach Earth’s surface. Also sunspot maximum will occur in 2013.

4. Dec 21, 2012 is a significant celestial date.
TRUE: Every year, December 21 is the winter solstice when the sun makes its lowest trip across the sky in the Northern Hemisphere.

5. The Maya used the 26,000-year precession cycle to predict events in 2012.
FALSE: The Maya may have observed slow changes in the sky due to precession, but this cycle was never recorded.

6. There will be a cataclysmic event in 2012.
TRUE: There will be volcanic eruptions, floods, earthquakes, tornadoes, and hurricanes in 2012 – just like every year on our dynamic planet.

7. An impending pole shift will tear the Earth apart in 2012.
FALSE: The poles wander at a speed of about 1 degree per million years.

8. There is a special alignment of the sun in front of the Milky Way galaxy on Dec. 21, 2012.
TRUE: On the winter solstice, the sun is now in front of a dark rift in the Milky Way band, close to the direction of the Galaxy’s center as it has been for several years.

9. A rogue planet, such as Nibiru or Eris or Planet X, is going to destroy the Earth in 2012.
FALSE: Eris is now beyond Pluto. There is no Planet X. The Babylonian Nibiru was probably Jupiter. The Maya only knew Mercury, Venus, Mars, Jupiter, and Saturn.

10. A geomagnetic reversal in 2012 will devastate the planet in 2012.
FALSE: Geomagnetic reversals do happen and we may be overdue for one. These take thousands of years to occur and are not destructive.

11. A “global awakening” is coming in 2012, leading to a societal transformation.
TRUE: Well, 2012 is a presidential election year for the United States and for Mexico and the diamond jubilee of the Queen.

12. The Earth will pass through the Galactic plane.
TRUE: The Earth will cross the Galactic Equator, but in about 27 million years.

Come learn more about Maya culture and their calendar in our new Planetarium show, 2012: Mayan Prophecies, open now.

Go Stargazing! May Edition

Saturn is the only planet in May 2011 evening skies.  Face south southeast at dusk, and you’ll see Saturn near a star of similar brightness— Spica in Virgo.  Saturn is significantly higher in the sky than Spica and a bit to its right as you face south.  Last month, Earth passed between the Sun and Saturn.  That alignment, called opposition, put Saturn in the sky all night long.  The ringed planet is now well placed for evening viewing, and remains in the evening sky until late September 2011.

mars-06-crop
Mars
Creative Commons License photo credit: chipdatajeffb

The other four naked eye planets are involved in a very close gathering low in the east at dawn.  You will need a clear view all the way to the east northeastern horizon at daybreak to observe this planet massing.  However, the planets do outshine all stars in this general area. If you’re able to observe any points of light just above the horizon as dawn begins, you’re probably seeing the planets.  As of now, Venus and Mercury rise first, with Mercury about a degree under the brighter Venus.  Mars and Jupiter are a bit to their lower left, with Mars a little to the left of Jupiter.  Mars was less that half a degree above Jupiter on May 1, and is now slowly pulling away from it.  Venus and Mercury are moving faster, so they are closing the gap on Mars and Jupiter.

On the morning of May 11, Venus and Mercury will be aligned with Jupiter, with Venus less than one degree from Jupiter.  This is also when the entire grouping is the most compact, with all four planets within six degrees of one another.  By May 21, Mercury and Venus will have caught up with Mars, with Venus just over a degree from the red planet.  After this, Mercury and Venus pull ahead of Mars and thus go deeper into the sun’s glare.  Mars and Jupiter, left behind, remain in the morning sky all summer.

Star Gazing
Creative Commons License photo credit: jurvetson

A swath of brilliant winter stars sets in the west at dusk this month.  Orion, the Hunter, is still visible in the west as May begins.  His two dogs, represented by Sirius and Procyon, are to his left.  To Orion’s right is Taurus, the Bull, with the star Aldebaran as its eye. Gemini, the Twins, are above Orion.  The Big Dipper is above the North Star, with its handle pointing to the right.  From that handle, you can ‘arc to Arcturus’ and then ‘speed on to Spica;’ those stars are in the east and southeast at dusk.  Leo, the Lion, passes almost overhead in late evening.

As Orion and Taurus set, look for Antares, brightest star of Scorpius, the Scorpion, to rise in the southeast.  At the same time, Vega, brightest star of the Summer Triangle, appears low in the northeast.  These stars remind us that summer is on the way.

Moon Phases in May 2011:

New Moon                              May 3, 1:50 a.m.

1st Quarter                             May 10, 3:32 p.m.

Full Moon                               May 17, 6:07 a.m.

Last Quarter                          May 24, 1:51 p.m.