If you have watched the early evening sky over the past weeks, you may have noticed Venus, Mars, and Saturn engaging in a slow planet dance.

On August 12 and 13, the Moon joins the party. Look for this striking sight soon after sunset in the same direction the Sun went down. You will likely see the crescent Moon and super bright Venus first. As the sky darkens further, notice Mars and Saturn near Venus. (Mercury will be lower, dimmer, and much harder to spot.)

If you’d like to see these celestial objects through a telescope, join Morehead for our skywatching session this Thursday, August 12, from 9 to 11 p.m. Weather permitting, we’ll be at Jordan Lake, Ebenezer Church Recreation Area. Come near the beginning of the session to view the Moon and planet trio. Then stick around for a chance to see some Perseid meteors.

If the skywatching session is canceled, we will post a message around 4 p.m. at the Morehead Web site — please check before you head out to Jordan Lake.

Amy Sayle hopes to spot a few Perseid meteors from Jordan Lake during Paddling Under the Stars. Although the paddle is sold out, the skywatching session is free and open to all.

Starlight from Arcturus opened the 1933 Chicago World's Fair.

Starlight from Arcturus opened the 1933 Chicago World's Fair.

If you want to wish on the first star you see tonight, there’s a good chance it’ll be Arcturus.

As you make your wish, you can also think about how Arcturus became famous in 1933 when its starlight opened the Chicago World’s Fair. On May 27, at 9:15 p.m. central time, several observatories aimed telescopes at Arcturus and focused its light onto photocells. The current that was generated resulted in the flipping of a master switch for the fair’s lights.

According to an article published the next day in the New York Times, “the grounds, pavilions and waterways of the fair were drenched with light. Thousands of awed beholders broke into cheers.”

Why was Arcturus chosen for this honor? It was thought to be 40 light years away, meaning that the light reaching Earth in 1933 would have left Arcturus forty years earlier, in 1893—when Chicago previously hosted a World’s Fair.

Unfortunately, they picked the wrong star. We now know that Arcturus is actually about 37 light years away.

So if you spot Arcturus tonight, you see it as it looked 37 years ago, in 1973, when the light left it. Looking deep into space is like having a time machine into the past.

To learn to identify Arcturus and other stars and constellations, come to Morehead’s skywatching session on Saturday, June 19. Or register for Starry Summer Nights; this class for adults takes place Tuesday evening, June 22, under the planetarium dome.

Arcturus is probably pretty much the same now as in 1973, but it’s still fun to think about.

Evening planets on May 24, 2010

Three planets are visible in the current evening sky: Venus, Mars, and Saturn.

But how do you tell a planet from a star?

1)      By how it looks.

Whereas stars twinkle, planets generally shine more steadily. Planets can also look very bright—especially Venus. Currently in the western evening sky, it’s the brightest object other than the Moon. Also in the evening sky are Mars and Saturn, which are roughly as bright as the brightest stars appearing near them.

2)      By where it is.

Stars appear all over the sky, but you won’t find planets just anywhere. Because they orbit the Sun in roughly the same plane, planets always appear within a certain band in our sky—the zodiac. Right now Venus appears to be near the feet of the Gemini Twins, Mars is about to munched on by Leo the Lion, and Saturn looks like Virgo the Maiden’s earring. (Side note: Many people are familiar with the 12 astrological signs of the zodiac, but there are more than 12 astronomical constellations of the zodiac that planets can appear in. Mercury, for example, was recently hanging out inside the boundary of Cetus the Sea Monster.)

3)      By how it moves over time.

Watch a planet night after night, and eventually you’ll notice it appears to wander against the background of the stars. Learn to identify the zodiacal constellations, and then you’ll know that any “extra” star is probably a planet. For an animation of the changing positions of the planets over the next few weeks, view the May 15th Carolina Skies segment on WRAL.

Over the next few months Venus, Mars, and Saturn will appear to close in on one another. See their progress at Morehead Planetarium and Science Center’s next skywatching session on Saturday, June 19. Weather permitting, we’ll be at Jordan Lake’s Ebenezer Church Recreation Area from 9 to 11 p.m.

Amy Sayle is Morehead's Science 360 manager.

Certified Genetic Counselor Patricia Devers presented Morehead’s Current Science Forum in May.

What if you could decide what traits you want in your baby – a certain eye color, hair color, even intelligence level?

At Morehead’s Current Science Forum on May 6, reproductive genetic counselor Patricia Devers explained that because of the complexity of non-medical traits, we’re nowhere close to being capable of designing babies in the way you might select the options you want in your next car.

However, preimplantation genetic diagnosis (PGD) can currently be used to screen embryos with certain diseases or conditions. (PGD can be done on embryos created by in vitro fertilization; PGD differs from prenatal testing, which can be done only after a woman is already pregnant.)

At the Current Science Forum, Devers posed a series of ethical questions to the audience, including:

  • Should a woman who is a carrier for the sex-linked disorder Duchenne muscular dystrophy be allowed to use PGD to avoid the birth of a boy who, because of his sex, would have a 50% chance of having the disease?
  • What about a couple who wants to use PGD to avoid the birth of a boy because they already have four boys and really want a girl?
  • Should a couple be allowed to use PGD to have a child with slow twitch muscles, so that the child may be better equipped to run marathons?

Although many countries regulate the use of PGD, no laws in the United States cover its use. Instead, these questions are being answered in this country by couples and their physicians.

To join in on additional thought-provoking discussions of current scientific issues, please come to Morehead’s next Current Science Forum.

Amy Sayle is Morehead's Science 360 manager.

April 1, 2010, 45 minutes after sunset

April 1, 2010, 45 minutes after sunset

Have you ever seen Mercury? Most people haven’t. Impress your friends and family by pointing out Mercury to them during the next week—the best time this entire year to see this elusive planet in the evening sky.

First, find Venus. It’s that very bright point of light low in the west soon after sunset.

Next, look for Mercury. It’s to the lower right of Venus and much dimmer. For the next ten days, these two planets appear to lie within just a few degrees of each other (less than half the width of your fist held at arm’s length).

For the best chance of identifying Mercury, go out about 45 minutes after sunset in the next week (try ~8:20-8:30 p.m. for the Triangle area). You’ll need clear skies and a view of the western horizon that is as building- and tree-free as you can manage.

If you look too soon after sunset, you may have trouble picking out the planet in the still-bright sky. Look too late, and Mercury will have dropped below the western horizon (or at least behind all those trees in your neighborhood). Later in April, Mercury disappears altogether from the evening sky.

Please join Morehead at our next skywatching session at Jordan Lake on April 17, 2010. We’ll see Mercury and Venus near the beginning. Mars and Saturn will also be visible. Bring your friends and family!

Amy Sayle is Morehead's Science 360 manager. She looks forward to helping people learn to identify planets and stars in Morehead's Beginning Skywatching course for adults, starting April 7. To register online, go to moreheadplanetarium.org, click Events & Activities, then Adult Classes.

Orion the Hunter

Orion the Hunter

How well can you see the stars from where you live? Through March 16, you and your family can collect scientific data right outside your house (or anywhere you choose) for GLOBE at Night, an annual worldwide project to measure light pollution.

Participating is easy:

1)  Go outside at least an hour after sunset between now and March 16, and wait 10 minutes or more for your eyes to adjust to the dark.

2)  Find the constellation Orion, and compare what you see with the GLOBE at Night magnitude charts.

3)  Go online to report your results.

The Globe at Night Web site provides helpful activity packets with printable magnitude charts. A few weeks from now, the organizers will release a map of light pollution levels worldwide—including your data point.

To experience skies that may be darker than at your home (or maybe not, depending on where you live), join Morehead Planetarium and Science Center for a skywatching session. We’ll be at Little River Regional Park on Friday, March 19, and at Ebenezer Church Recreation Area at Jordan Lake on Saturday, March 20. Both sessions are 8 to 10 p.m. and are weather permitting.

You can also visit Morehead at 8 p.m. on either April 23 or 24, when we will use our new technology to present the live planetarium program “Our Vanishing Night.” Telescope observing will follow, weather permitting.

Amy Sayle is Morehead's Science 360 manager. One year while leading a stargazing seminar at the North Carolina Center for the Advancement of Teaching, she and the seminar participants documented a sky of limiting magnitude 6 at Ocracoke Island, NC. How dark is YOUR sky? Please leave us a reply.

Geminid meteors appear to originate from the constellation Gemini the Twins (Image: Stellarium)

Geminid meteors appear to originate from the constellation Gemini the Twins (Image: Stellarium)

The annual Geminid meteor shower peaks tonight (Sunday night, Dec. 13 – Monday morning, Dec. 14).  Yes, it will be cold.  But there are four reasons why it’s worth bundling up and heading outside to look:

1) You can view the Geminids as early as 9 or 10 tonight, with the most meteor activity expected around 1 or 2 a.m.  Compare this with other major meteor showers, which require going out at an insane hour for the best viewing.

2) This is a strong, reliable shower. From a dark location, you can expect to see an average of one or two meteors (“shooting stars”) streak across the sky each minute.

3) No moonlight will wash out dimmer meteors from view, as they did for last year’s Geminids. This time the Moon is a waning crescent and won’t rise till almost dawn.

4) As I write this, the Clear Sky Charts for most of North Carolina, including the Triangle area, predict clear skies this evening.

To view the Geminids, wear really, really warm clothes, a hat, and gloves, and wrap yourself in a sleeping bag or blankets. Find a safe location without too many trees or unshielded outdoor lights nearby to hurt your view.

Allow your eyes about 15 minutes to adjust to the dark, and watch the sky from your sleeping bag or reclining lawn chair. The Geminids are named for the constellation they appear to radiate from, but you do not need to know how to find Gemini to spot the meteors.

Check the Web sites for Sky and Telescope and the American Meteor Society for details about the peak, duration, and origin of the Geminid meteors.

If you want to learn to identify those Gemini twins as well as what else is up in the night sky over the next few months, you can register for Starry Winter Nights. This adult class happens Wednesday evening, Dec. 16. And if you missed the 2009 Geminids, we can re-create them in the star theater with the push of a button.

Amy Sayle is Morehead's Science 360 manager. She looks forward to teaching Starry Winter Nights in Morehead's climate-controlled star theater.

Bella is having a very bad day and is not up for remembering her astronomy.

Bella is having a very bad day and is not up for remembering her astronomy.

Today is the new moon. A different New Moon happens Friday, when the second movie made from Stephenie Meyer’s popular Twilight book series opens in theaters.

Although Twilight fans may not care, our heroine Bella Swan’s knowledge of lunar phases is questionable. In the book’s title-inspiring scene, in which her vampire boyfriend Edward leaves her and she wanders through the woods for hours, Bella thinks, “Tonight the sky was utterly black. Perhaps there was no moon tonight—a lunar eclipse, a new moon.”

Bella correctly equates “new moon” with “no moon.” A new moon is above the horizon only during the day, and the only lit part is the far side that we can’t see.

But Bella’s phrasing suggests a few astronomical impossibilities:

1) In her distress, is Bella thinking a lunar eclipse and new moon are the same? Her thoughts are ambiguous. But a lunar eclipse can happen only when the moon’s phase is full. Never when it’s new. Not even in fictional worlds with vampires.

When the moon is new, it’s between the sun and Earth, as Meyer describes on her Web site. A lunar eclipse, however, requires a different geometric line-up: Sun-Earth-Moon.

Lunar eclipse geometry

Only in this configuration can the Earth’s shadow cover (eclipse) the moon. MrEclipse.com explains why lunar eclipses don’t happen every full moon, and NASA’s lunar eclipse page lists dates of past and future lunar eclipses.

2) Even during a lunar eclipse, Bella wouldn’t have “no moon tonight.” The moon remains visible when eclipsed by the Earth’s shadow. Although the moon darkens, sometimes almost to the point of invisibility, it won’t completely disappear because Earth’s atmosphere bends sunlight. An eclipsed moon usually looks reddish (not to be confused with the reddish tint the moon can take on when near the horizon, regardless of its phase).

This total lunar eclipse did not happen at new moon. (Credit: Fred Espenak)

This total lunar eclipse did not happen at new moon. (Credit: Fred Espenak)

3) Even with no moon, the sky wouldn’t look “utterly black” in Forks, Washington, where Bella wanders the woods, unless there was a regional power outage. Because of light pollution, there are no truly dark skies in the entire state. But we can forgive Bella for exaggerating in her distraught condition.

Six months later (warning! spoiler ahead!), things brighten up for Bella when she reunites with Edward in Italy. There they further mangle the solar system by experiencing an impossible sun. That’ll be another blog post.

Do you have an example to share of impossible astronomy in a book?  Please post a comment.

Amy Sayle is Morehead's Science 360 manager. She doesn't let impossible astronomy get in the way of enjoying a good story.

MESSENGER took this image of Mercury on September 29, 2009, during its third flyby.  This image shows portions of the planet’s surface never seen before by spacecraft.  (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

MESSENGER took this image of Mercury on September 29, 2009, during its third flyby. This image shows portions of the planet’s surface never seen before by spacecraft. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

Early tomorrow morning (Thursday, October 8th) will be a good time to spot a rarely seen planet—Mercury.

About 45 minutes before sunrise, look for Mercury low in the east and hanging out just a smidgen below and to the right of Saturn. You’ll need an unobstructed horizon because even at its best placement in the sky, Mercury never appears far from the Sun.

Mercury is not only rarely seen by humans, it hasn’t been seen much by our spacecraft either.  NASA’s MESSENGER spacecraft, which recently flew by the planet, is only the second to visit Mercury, and in March 2011, it will be the first to orbit it. Mercury’s first visitor, Mariner 10, flew by the planet in 1974-75.

The scientific goals of the MESSENGER mission include answering questions such as why is Mercury so dense and what is its geological history and the nature of its magnetic field. You can learn more about this mission at NASA’s MESSENGER Web site.

Amy Sayle is Morehead's Science 360 project manager. She's considering setting her alarm clock for 6:30 a.m. to see Mercury.

Io passing in front of  Jupiter. (Credit: Cassini Imaging Team, Cassini Project, NASA)

Io passing in front of Jupiter. (Credit: Cassini Imaging Team, Cassini Project, NASA)

In the Science 360 program “Bring the Universe to Light,” MPSC educators tell the story of Galileo Galilei’s surprising observations of the planet Jupiter.

With a telescope or even just a decent pair of binoculars, you can discover what Galileo did 400 years ago: Jupiter has moons that orbit it. This observation contradicted a commonly held view that everything revolved around Earth.

Tonight, something special happens with these dancing points of light that Galileo observed. Two moons, Ganymede and Europa, will appear to cast dark shadows on Jupiter as they pass in front of the planet. And Io will disappear as it passes behind.

The Chapel Hill Astronomical and Observational Society invites the public to join them for an informal telescope viewing of this moon dance after 9 p.m. tonight, Wednesday, Aug. 26, at Farrington Point, Jordan Lake. (Please note this is not the same place where the regular Morehead skywatching sessions meet.)

Amy Sayle is Morehead's Science 360 manager.


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