Upcoming Total Lunar Eclipse on August 28th, 2007

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By the end of August, you might be just cooling down from the excitement of the Perseid meteor show, but it’s time to gather the friends and family again for another fantastic sky show – a total lunar eclipse on Tuesday, August 28th, 2007. This is going to be one of most popular, visible from 5 continents, including most of North America. Got that, set your calendar right now.

If you live in Western North America like me, you know we’ve gotten the short end of the lunar eclipse stick for the past few years. Well, now’s our time to shine in the ruddy glow of a fully eclipsed moon. This is the one we’ve been waiting for.

The eclipse will begin just after midnight August 28th for folks in Pacific Daylight Time – 12:54 am PDT. It won’t look like much in the beginning, but then the Earth’s shadow will slowly start to darken the Moon. Around 2 hours later, at 2:52 am PDT, the eclipse will reach totality, when the Moon is fully in the Earth’s shadow. It will change from grey to red, and stay that way for another 90 minutes. Then it will exit the shadow again just before dawn.

The eclipse will be visible from Australia, Japan, parts of Asia and most of the Americas. Unfortunately, it won’t be visible to observers in Africa or Europe. Since the eclipse gets a late start, we’ll get a good view on the West Coast of North America; as long as you’re willing to stay up late. Eastern observers will need to bring coffee, since their view won’t wrap up until 7:22 am EDT.

Here’s a special web page from NASA on the eclipse, providing diagrams and starting times for this event. I’ll provide another reminder as we get closer to the 28th, I just wanted to make you aware, and encourage you to set that evening aside for a wonderful sky show.

Original Source:NASA Eclipse Information

Will Mars Look as Big as the Moon on August 27? Nope

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Every year around this time, an email circulates across the Internet speculating that on August 27th, Mars will look as big as the Moon in the sky. And every year, I go ahead and debunk it. Here’s a link to last year’s version. Once again, I’d like to inoculate all my Universe Today readers, to make sure you understand what’s going on, and you’re prepared to explain to your eager friends why this non-event isn’t going to happen.

Say it with me. Mars won’t look as big as the Moon on August 27th.


This strange hoax first surfaced on the Internet back in 2003. An email made the rounds with the following text:

The Red Planet is about to be spectacular! This month and next, Earth is catching up with Mars in an encounter that will culminate in the closest approach between the two planets in recorded history. The next time Mars may come this close is in 2287. Due to the way Jupiter’s gravity tugs on Mars and perturbs its orbit, astronomers can only be certain that Mars has not come this close to Earth in the Last 5,000 years, but it may be as long as 60,000 years before it happens again.

The encounter will culminate on August 27th when Mars comes to within 34,649,589 miles of Earth and will be (next to the moon) the brightest object in the night sky. It will attain a magnitude of -2.9 and will appear 25.11 arc seconds wide. At a modest 75-power magnification

Mars will look as large as the full moon to the naked eye. By the end of August when the two planets are closest, Mars will rise at nightfall and reach its highest point in the sky at 12:30 a.m. That’s pretty convenient to see something that no human being has seen in recorded history. So, mark your calendar at the beginning of August to see Mars grow progressively brighter and brighter throughout the month. Share this with your children and grandchildren. NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN

There are a few problems with this. The first problem is that the email doesn’t actually mention the date; it just says August 27th. This means it can live on for years and years, going around and around the Internet, forwarded by gullible people to their friends.

The second problem is that it’s wrong. Mars isn’t going to be making a close approach on August 27. The close approach this email is discussing happened back in 2003. It did indeed get closer than it had in at least 50,000 years, but this was a very small amount. On August 27th, 2003, Mars closed to a distance of only 55,758,006 kilometers (34,646,418 miles). The Moon, by comparison, orbits the Earth at a distance of only 385,000 km (240,000 miles). Mars was close, but it was still 144 times further away than the Moon.

Instead of appearing as a huge red orb in the sky, Mars looked like a bright red star. Observers around the world set up their telescopes, and took advantage of this close encounter. But you still needed a telescope. And if you read the email carefully again, you’ll see that it’s trying to explain that.

There’s an extra paragraph break. The last sentence of second paragraph is hanging. It says, “At a modest 75-power magnification “, but there’s no period. The next paragraph starts up with the text, “Mars will look as large as the full moon to the naked eye.” In other words, if you put one eye into the telescope and looked at Mars, and kept your other eye looking at the Moon (which isn’t actually humanly possible), the two orbs would look roughly the same size.

Mars and Earth do come together every two years, reaching the closest point on their orbits – astronomers call this “opposition”. And we’re in one of those years. But it’s not going to happen on August 27th. Instead, we’ll make our opposition on December 18th, 2007. At this point, Mars will be 88.42 million km (55 million miles) – further away than its 2003 opposition.

NASA is taking advantage of the upcoming opposition, and will launch the Phoenix Mars Lander in August. The spacecraft will make its shortest possible journey to reach Mars, arriving early next year.

And by next July, it’ll be time to write this article all over again.

Prototype Moon Rovers Tested in the Arctic

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The question of whether humans or robots should explore space has been decided by NASA: it’ll be both. In the future, NASA anticipates that humans will work with robotic explorers to gather and analyze data more efficiently than either could do alone. This will be the eventual scenario when humans set foot on the Moon again, as part of the Vision for Space Exploration.

Two prototype Moon rovers are currently crawling around a polar desert in the Arctic Circle, helping scientists develop the skills and experience they’ll need to do this for real on other worlds. The robots are named K10 Black and K10 Red, and carry 3-D laser scanners and ground-penetrating radar.

They arrived at the Haughton Crater on Devon Island, Canada on July 12, and will continue their operations until July 31. The robots are using different techniques to study the interior of the 20 km (12.4 mile) crater. For example, their 3-D laser scanner can map topographic features as much as a kilometre away, and the ground penetrating radar can peer down 5 metres. The robots are just covering the terrain like lawn mowers, mapping it out strip by strip.

Over the course of the study, the rovers will cover an area of approximately 120 acres of terrain, operated completely remotely from the Haughton-Mars base camp located several kilometres away.

Original Source: NASA News Release

Flashes on the Moon Caused by Gas

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There’s a strange phenomenon on the Moon that has puzzled astronomers for hundreds of years. They’re called transient lunar phenomena (TLPs), and they look like a brief flashes, changes in colour, or blurring on the surface of the Moon.

Astronomers have argued about what’s really going on for years. Some possible explanations include turbulence in the Earth’s atmosphere, physiological effects in the human eye, smearing of light, and even psychological causes. But according to new research by Columbia University astronomy professor Arlin Crotts, radon gas leaking out from the Moon is probably the best explanation.

Cotts correlated TLPs with known gas outbursts on the lunar surface as seen by several spacecraft, including NASA’s Apollo 15 mission. He found a surprising correlation between the outbursts detected by the spacecraft, and reports from observers of TLP sites.

The researchers are now building a robotic camera on the Cerro Tololo Inter-American Observatory in northern Chile. It will scan the moon every few seconds, and produce an unbiased map of TLPs.

Perhaps this will settle the mystery, once and for all.

Original Source:Columbia News Release

Explaining the Moon Illusion

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Have you ever marveled at how large the full Moon looks when it’s just peeking up over the horizon? It looks so much larger than when it’s high in the sky. It’s not changing in size, your brain is tricking you.

This is called the Moon Illusion, and people have noticed it for thousands of years. If you take a camera and capture images of the Moon all the way from the horizon until it’s at its highest point, the size stays exactly the same. But from your perception, it’s huge on the horizon and much smaller when it gets higher.

You can even confirm this without a camera. Hold your hand out at arm’s length, and the full Moon is about the size of the tip of your pinky finger. Do this when the Moon is down near the horizon, and then do it again when it’s much higher and you’ll see, it’s exactly the same size.

So, why is this happening? Researchers think that the shape of the sky could be the cause. The Moon moves in a circular shape around us, but the sky and clouds are in a bowl shape above us. This difference causes our brain to perceive the Moon larger when it’s down at the horizon.

Bad Astronomer Phil Plait recently explained this for Wil Wheaton on his blog:

The illusion is a combination of two things. the first is the Ponzo illusion, where your brain interprets things as being bigger if it thinks they are farther away.

Second, the sky is not exactly hemisphere-shaped to our brains, it actually looks like an inverted bowl. Think of it this way: clouds overhead are maybe two miles up, but clouds near the horizon are a hundred miles away. So the sky looks bowl-shaped.

So when the Moon is on the horizon, your brain thinks it’s farther away than when it’s overhead. The Ponzo illusion kicks in, and your brain gets fooled into thinking the Moon is HUGE. As it gets higher, the illusion vanishes. If you actually observe the Moon with binoculars or with a ‘scope, you can see it is no bigger on the horizon. In fact, it should look smaller because it’s a few thousand miles farther away than when it’s overhead.

So when your friends are admiring the huge moon, hanging low in the sky, feel free to let them in on the secret.

It’s all an illusion.

Original Source: [email protected]

Science Experiments that Astronauts will Deploy on the Moon

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NASA announced that it has selected 7 new experiments that might be carried to the Moon as part of the Vision for Space Exploration. Each of these missions would be “suitcase science” experiments, which the astronauts could easily deploy them onto the surface of the moon as part of a mission.

The experiments include:

  • Autonomous Lunar Geophysical Experiment Package – NASA/JPL
  • Lunar Laser Transponder and Retroreflector Science – NASA/JPL
  • Volatile Analysis by Pyrolysis of Regolith on the Moon using Mass Spectrometry – NASA/Goddard
  • Seismology and Heat flow instrument package for Lunar Science and Hazards – NASA/Goddard
  • Lunar Radiation Environment and Regolith Shielding Experiment – SWRI
  • Lunar Suitcase Science: A Lunar Regolith Characterization Kit – U.S. Army
  • Autonomous Lunar Dust Observer – Ball Aerospace

NASA chose these winning proposals out of 70 submissions under the Lunar Sortie Science Opportunities Program.

Original Source: NASA’s Jet Propulsion Laboratory

Plans for a Liquid Lunar Telescope

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NASA-funded researchers are working on a clever technology that could deploy a gigantic telescope made from rotating liquid… on the Moon! It sounds like science fiction, but they’ve gotten smaller prototypes to work, and the technology should work even better on the lower lunar gravity.

Here’s how it works. Astronauts would deliver the observatory (all folded up) to the Moon during one of their upcoming “return to the Moon” missions. It would unfold into the shape of a telescope mirror made of mesh. The astronauts then pour a reflective liquid onto the mesh. The mesh rotates coating the entire surface in the liquid. Don’t worry about the liquid dripping through the mesh, it actually gets held in place by surface tension.

As telescopes go, this would be a whopper. The current plans call for a 20-metre mirror, but it could theoretically get as big as 100-metres across. This would provide 1000 times the observing power as the James Webb Space Telescope, which still won’t launch for a few more years. That gives it the power to look right back to the very edge of the observable Universe, and see the first generations of stars forming.

Now there’s a reason to send humans back to the Moon.

Original Source: NASA News Release

Japanese Moon Probe Nicknamed KAGUYA

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The Japanese Aerospace Exploration Agency announced that they’re giving their SELenological and ENgineering Explorer (aka SELENE) a new nickname: Kaguya. Now I know it’s not the hugest news in the aerospace industry, but I haven’t actually given many words to this lunar mission. So, now I’ve got an excuse. For those of you with some Greek mythology knowledge, Selene was the Greek Moon goddess, so the name SELENE is actually pretty clever.

The mission will consist of 3 different spacecraft: a relay satellite, the VRAD satellite, and the Orbiter. If all goes well, they’ll launch together on July 1, 2007 atop an H-IIA rocket from the Tanegashima Space Center into a lunar trajectory. 5 days later, the trio will reach the Moon, and then go into an extremely eccentric orbit, varying between 120 and 13,000 km (75 by 8,100 miles).

Over time, the relay and VRAD satellites will move to lower, but still eccentric orbits. The orbiter will go into a nice, tight 100 km (62 miles) circular orbit.

The purpose of SELENE will be to perform a global survey of the Moon, determining its elemental abundance, minerals, topology, gravity and other aspects that will help future lunar exploration – especially important when humans set foot on the Moon again.

The VRAD satellite has a different job to do. It’ll measure the position and precession of the Moon very very carefully. Once again, very important when you’re sending future missions back to the Moon.

So, by a popular vote in Japan, SELENE was nicknamed Kaguya. This comes from a 10th century Japanese folktale. You can read the Wikipedia entry for a full description.

Original Source: Jaxa News Release

Blue Moon on May 31st, 2007

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On Thursday, May 31st, 2007, the Moon will be full again, like it does every 29 days. But according to some traditions, it’ll be a special Blue Moon, since it’s full for the second time in May. The first full Moon occurred on May 2nd, and now, still in May, there’s time for another full Moon.

The concept of a Blue Moon has been around for hundreds of years, but the modern definition appeared in the last century. There was a reference to it in books like the Maine Farmer’s Almanac, and an issue of Sky and Telescope in 1946 entitled “Once in a Blue Moon”.

Sky and Telescope has a detailed analysis here. And here’s more information from NASA.

Does anything special happen to the Moon? Nope, it’s just a quirk of the dates, since 29 days can fit inside the 30/31 days we have in a month.

To complicate the matter, though, there are times when the Moon can look blue. If there are tiny droplets of water in the air, they strongly scatter red and green light while allowing other colours to pass through. A moonbeam passing through a wispy cloud will turn a beautiful shade of blue.

So, tomorrow’s a Blue Moon, but it won’t actually be blue. And the Moon can turn blue, but it doesn’t have to be a full Moon, or a Blue Moon. The Blue Moon isn’t anything special, it’s just a trick of the dates. Did that make any sense?

Original Source: NASA Science Article