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.

F5 Tornado

Scientists working on the VORTEX2 project this month are combing the Great Plains in search of tornadoes. When completed in June, VORTEX2 will be the largest-ever study of tornadoes. Image by Justin Hobson.

Lightning flashes overhead, hail pounds mercilessly into the ground, and high winds threaten to bring down trees. Suddenly, a funnel cloud begins to snake down from the dark clouds above, kicking up dust and growing in size as it reaches the ground. If you are like most people, seeing something like this would probably make you want to run for cover. But for more than 100 scientists working with the VORTEX2 project, running for cover isn’t an option. Being up close and personal with tornadoes is their job, and over the course of the next month they will be patrolling the Great Plains region of the United States searching for these killer storms.

VORTEX stands for “Verification of the Origins of Rotation in Tornadoes Experiment.” As the name suggests, the project is attempting to discover exactly how, when, where, and why tornadoes form. Currently, weather forecasters can predict tornadoes with an average lead time of only 13 minutes, and 70% of tornado alerts turn out to be false alarms. VORTEX2, which runs from May 1 to June 15 of this year, will be the largest-ever tornado study, and the scientists involved hope to deploy an unprecedented array of cutting-edge technology into and around these storms.

The original VORTEX project took place in 1994 and 1995 and helped to inspire the 1996 film Twister. Data from that project helped to significantly improve tornado forecasting. The VORTEX2 project will build on the knowledge gained from its predecessor by using more advanced data collection tools and by extending the study period by two weeks. You can follow VORTEX2’s daily progress at the project website or blog.

If you are interested in learning more about tornadoes and other severe weather events, stay tuned to the Morehead website for information about a new live show that will debut on June 15 (the last day of the VORTEX2 project): “Science 360: Predicting Severe Weather.”

Casey Rawson is the Science Content Developer for Science 360.

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.

Massive Terrestrial Impact

A huge asteroid like the one in this image (an artistic rendering from NASA) would likely wipe out all life on Earth. But should we be worrying about this happening in 2012?

As if Mayan “doomsday prophecies,” Sun-damaging planetary alignments, and fatal alignments with the galactic center were not enough, 2012 apocalypse proponents are also stating that on December 21, 2012, Earth will be hit by a huge asteroid that will cause mass extinction and global chaos.

As with the other 2012-doomsday scenarios, the asteroid strike claim has a good deal of scientific evidence against it. Of course, asteroids have hit our planet before – scientists believe a huge one (several miles wide) was probably responsible for the extinction of the dinosaurs – and it is virtually guaranteed that Earth will be hit again at some point in the future. But precisely because of that high probability, scientists around the globe are searching the skies for what they call “Near-Earth Objects” (NEOs) that may one day strike Earth.

NASA, in conjunction with several other astronomical organizations around the globe, has been cataloging NEOs since 1998. These organizations search the sky for asteroids and comets that are in Earth’s celestial neighborhood. When one is found, advanced computer programs model the object’s future path, taking into account the object’s size and speed as well as the influences of gravity from the Sun, Earth, and other planets and moons in our solar system. As the object comes closer, we can gather more information about it and further refine this model.

But why are scientists spending so much time searching for NEOs – it’s not like we could stop them from hitting Earth, right? It may sound like something out of a big-budget blockbuster, but astronomers actually do think that we would have a chance of deflecting a comet or asteroid headed for Earth – if we discovered it well enough in advance. Proposed methods for NEO deflection include solar sails, “gravity tractors,” and rockets – but NOT nuclear weapons as seen in Hollywood, which would only break the object apart and send deadly mini-asteroids our way. Russia has recently announced preliminary plans to deflect the asteroid Apophis (which technically has a chance of hitting us in 2036, albeit a very small chance).

So, could an asteroid strike the Earth on December 21, 2012? Sure – but a strike is no more likely on this particular date than on any other. Scientists in the NEO discovery program have not found any large object that is likely to even pass close to Earth on this date, or on any other in the near future. Even if they did, it is likely that we could deflect such an object before it intercepts Earth’s orbit.

To find out more about the 2012 claims, stay tuned to the MPSC blog and plan to attend our Science 360 show “The Truth Behind 2012” when it opens in early February.

Casey Rawson is the Science Content Developer for Science 360. She prefers "Deep Impact" over "Armageddon," if only for the escaping-a-tidal-wave-on-a-moped scene.

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.

Light Pollution

Light pollution can drastically affect the number of stars visible in the night sky. Click on the picture to enlarge. Picture from http://stellarium.org.

Step outside the average suburban home at night, and you’re likely to see the fluorescent glow of streetlights, soft yellow light streaming from the windows of homes, and security floodlighting. One thing you may not be able to see is the night sky. The light sources around us at night can scatter photons upwards into our atmosphere, creating light pollution that blocks our view of the stars – particularly those stars that are smaller, farther away from Earth, or dimmer. For many urban and suburban dwellers, the only Milky Way they’ll ever see comes in a brown candy wrapper.

Astronomers try to monitor levels of light pollution, because it has serious consequences for scientists’ ability to study our universe (Earth-bound telescopes, just like our eyes, are hampered by light pollution). Astronomers can’t be everywhere in the world, though, so to effectively keep tabs on levels of light pollution around the world, they need the help of ordinary citizens.

From October 9th through the 23rd, you can participate in the Great World Wide Star Count along with thousands of other amateur observers around the world. The idea is simple – everyone will observe the same constellation (if you’re in the Northern hemisphere, you will observe Cygnus) and count the number of stars that are visible. Then, observers will post their results online, where they can also view the project’s results. To participate, simply visit the Star Count website and download an activity guide.

If you are interested in learning more about the relationship between light and astronomy, look for the Science 360 show “Bring the Universe to Light,” coming back on the schedule at Morehead Planetarium and Science Center later this fall.

Casey Rawson is the Science Content Developer for Science 360.

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.

Moonlight (and possibly clouds) will interfere with early morning viewing of the 2009 Perseid meteor shower.

The annual Perseid meteor shower peaks this Wednesday (August 12).

Last year I recommended going out to view the Perseids at the ridiculous hour of 4 a.m. I vividly remember both the many meteors I saw between 4 and 5 a.m., as well as the effort involved in staying awake at work in the hours that followed.

This year, you and I can justify not trying so hard for two reasons:

(1) The weather. The forecast doesn’t look terribly clear for the Triangle.

(2) The Moon. After about 11 p.m., moonlight will wash out the dimmer meteors from view. The almost last quarter Moon rises within a few hours after sunset and stays up the rest of the night.

Meteors are also known as “shooting stars,” but they’re not related to stars. Meteors are caused when Earth travels through space debris (that left by Comet Swift-Tuttle in the case of the Perseids). When the debris interacts with the Earth’s atmosphere, a flash of light is created.

Perseid meteors appear to radiate away from the constellation Perseus, but you don’t need to know how to find Perseus to see the meteors. Take a lawn chair or sleeping bag to a spot away from city lights, and look about halfway up the sky. Choose a direction that’s dark.

If skies are clear, the best times to look for Perseid meteors include Tuesday evening to Wednesday before dawn, and Wednesday evening to Thursday before dawn. The most activity will be between midnight and dawn. If you’re watching after the Moon has risen, look away from it to a darker part of the sky. After giving your eyes 15 minutes or more to adjust to the darkness, you may see a Perseid meteor every few minutes.

If the weather permits, Morehead will hold a special Perseids skywatching session from 9 to 11 p.m. this Wednesday, Aug. 12, at Jordan Lake (Ebenezer Church Recreation Area).

Amy Sayle is Morehead's Science 360 manager.


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