If you haven’t received one, they go something like this:

Planet Mars will be the brightest in the night sky starting August!

It will look as large as the full moon to the naked eye. This will cultivate on Aug. 27 when Mars comes within 34.65M miles of earth. Be sure to watch the sky on Aug. 27 12:30 am. It will look like the earth has 2 moons. The next time Mars may come this close is in 2287.

Sorry to disappoint, but the information is inaccurate. Like so much else on the Internet, it (once) had a kernel of truth to it, but has since gone awry.

In 2003, Mars had an exceptionally close opposition to Earth. (Opposition is when the Sun, Earth, and another far-away object lie in a straight line to one another. The object is therefore opposite the Sun in our sky.) Mars lies in opposition every 20 months or so, but in 2003, it occurred when Mars was near its closest point to the Sun, which put it unusually close to the Earth.

“Unusually close,” in this case, meant 34,649,589 miles. The Red Planet did appear six times larger and much brighter in our sky than usual, but it was nowhere near “as big as the full Moon.” The original email’s author did, in fact, use that phrase, but went on to mention that one would have to use a telescope and an eyepiece giving 75x power to see it. Naturally, those boring, technical details were dropped somewhere during the countless subsequent iterations of email forwards, changing the meaning of his simile.

Since then, like clockwork, each August the emails make their rounds through the Internet again. Mars isn’t even near opposition this August. That occurred last December.

You may be disappointed to find out the truth, but there’s a silver lining: if you stepped out on your back patio and saw Mars was as big as the full Moon, chances are that it would probably be the last thing you ever saw. Earth and Mars would not make good neighbors.

The first thing you would notice, aside from the pretty view, would be a wobble in the Earth’s rotation, as the two planets’ gravitational fields wreaked havoc with one another. This would be quickly followed by the Earth’s crust fracturing apart, as parts of it try to keep spinning and others don’t. Geophysical activity — earthquakes, volcanoes, freaking-mountain-high-fire-fountains-of-molten-death — would dispatch most of the Earth’s inhabitants rather quickly, and oceanic flooding would take care of the rest (until the oceans boiled away, that is). Any survivors would enjoy the pleasure of having the air pulled from their lungs as they rode large chunks of Earth’s crust into the void as the planet broke apart. Where the view would be spectacular, I imagine.

Sorry, I get carried away sometimes. But seriously, the email is fake.

“Whaaa?!? You’re doing astronomy posts again?” Looks that way. Stay tuned for more.

So I’ve been pretty bummed the past few years, as family responsibilities have kept me from seeing the past few eclipses. Especially when I see videos like this:

However, I am very glad for my friends, who apparently had great skies for this morning’s eclipse.

Now, if you’ll excuse me, I have to speak to the wife about giving it a shot in 2009. It’s been too long.

In this era of space telescopes, satellites, and Photoshop, it’s easy to forget that only a few decades ago, we had no idea of what space actually looked like. The task of communicating the wonders of space was left to the dreamers and artists, and we depended on them to stir our imaginations and passion for the universe.

Men like Chesley Bonestell and Jack Coggins took paint to canvas and created worlds and vistas that existed at the limits of imagination. Some of their art was eerily prescient, some of it was dead wrong, and some of it seemed to make no sense whatsover. Occasionally space was presented as a terrifying place. Occasionally, it was presented with whimsy. Nevertheless, these artists were the first space explorers, and they don’t get enough credit for it. Their work influenced a generation of young children to grow up and become scientists, engineers, explorers, and dreamers.

This wonderful collection of pre-space age art was gleaned from children’s books going all the way back to the late 19th century. Take a look and see if any of these look familiar to you. Even I was able to find a bunch that I owned as a young spaceMonkey.

UPDATE:
Donald Davis, an artist commissioned by NASA in the 1970s, has now graciously placed high resolution versions of his imaginative paintings into the public domain. Make sure you take a few quiet moments to peruse these as well.
H/T: Paleo-Future

One of my fondest memories was watching Cosmos as a preadolescent and feeling for the first time the Sirenic-call from astronomy and physics — a secular passion which dominated the next 20 years of my life. I spent the 80s and 90s immersed in astronomy. I invested in telescopes, subscribed to astronomy magazines, devoured countless nonfiction works from Sagan and his colleagues, led one of the largest and oldest amateur astronomy organizations in the Midwest, volunteered at observatories, lectured at science museums, and majored in astrophysics while at college.

As happens to us all, my priorities changed as I got older and my family grew. Astronomy plays only a little part in my secular life now, as a modest hobby. But whenever I stand under the quiet, velvety expanse on a clear night, armed only with a small telescope and a red flashlight, I hear the sirens calling, and I know that it all started with the seed planted by that PBS series in 1980.

So I respect and appreciate him for that.

On the other hand, I have always had mixed feelings about Sagan. Superficially, you’d think I’d be the biggest fan of the world’s most famous science writer. But I was intrigued, for instance, by how little respect Sagan got from academia. The public’s view of Sagan was one of a man esteemed by his colleagues, leading the field of 20th-century astronomy; in fact, that’s not necessarily the case. Certainly, Sagan did his share of research, and his scientific career was nothing to slouch at, but he wasn’t necessarily known as a leader in his field. Many colleagues were irked that Sagan got his academic appointments based on his fame, not his credentials. Rumors abound of an underground “anti-Carl” attitude at Cornell, where students and faculty quietly fumed at how rare he actually appeared on campus, in between book tours and Tonight Show appearances.

Another troubling thing about Sagan to me was his sometimes contradictory attitudes toward critical thinking, scientific method, and even religion. The Demon Haunted World is one of my favorite non-fiction tomes, and if you haven’t read it, I urge you to do so. The book is essentially a lecture against the perils of non-critical thinking, and contains lessons for anyone whose life contains the need for effective persuasion (scientists, doctors, lawyers, educators, parents, etc.). Included is the famous Baloney Detection Kit, a set of guidelines to which successful critical thinkers should adhere.

Sprinkled throughout the book, Sagan excellently debunks the more famous examples of pseudoscience, like crop circles, magical religious healers, and so forth. But on numerous occasions, Sagan falls prey to the same foibles against which he lectures so strongly; engaging in ad hominem and straw man attacks against any who don’t hold his political or religious views.

The same pitfalls were shown in his book/movie Contact, where all non-scientific characters were presented as antagonists, and as stereotypical caricatures (a blundering priest who emotionally scars a young girl; a new-age religious hippie who quits priesthood “because of the celibacy thing”; a terrorist who kills because, well, because his faith directs him to; a fanatical right-wing religious politico; reactionary warmongers; etc.).

I remain honestly puzzled as to the current ‘fad’ of modern intellectuals who practically attempt to deify Sagan. I think he would have found that deliciously ironic.

To me, Sagan’s most enduring legacy should be his contagious attitude about the wonders of the cosmos, and the diminutive, humble place humans occupy in the universe. Second, as a writer, he should be given props for his talent in expressing the ridiculously complex in ways that laypersons could grasp, like in this scene from Travels in Space and Time, where he cogently explains relativistic time dilation:

Often, he would begin a lecture with a single sentence that would completely hook his audience:

“In order to make an apple pie from scratch, you must first create the Universe.”

Every time I hear that lecture, I must admit I get goose bumps.

That type of effective persuasion and contagious enthusiasm is becoming rare among science popularizers. Those still “holding the candle” include Neil deGrasse Tyson and Brian Greene, two more authors whose works you should devote some spare time to reading.

Now, if you’ll excuse me, I’m getting an urge to watch The Edge of Forever again.

Link

HT: nickjsky

A transit occurs when a planet interior to our own (Mercury or Venus) crosses directly in between the Earth and the Sun. What we see is a black disk crossing the face of the Sun over a period of several hours.

Venus transits the Sun in the summer of 2004

The transit begins at 2:12 p.m. EST, and lasts for about five hours.

Note: Do not observe the Sun without proper protection. Sunglasses don’t count. Only use approved solar filters when looking at the Sun, or better yet, rig up a simple projection system.

Projecting the Sun’s image onto a piece of cardboard

NASA’s Exploratorium has an article with instructions on how to view it safely. You may want to check out Larry Koehn’s animated simulation of the transit.

There once was a spacecraft named Hubble,
whose finances fell into trouble.
When its budget runs dry,
it will fall from the sky
and break up into nothing but rubble.

But it won’t happen anytime soon…

What’s New
Almost everything in the solar system orbits the Sun in a narrow band called the ecliptic. Think of it this way: If all the planets were orbiting the Sun like marbles swirling on a plate, then the thickness of the plate would define the ecliptic. From Earth’s vantage point, the ecliptic traces a line across our sky that mirrors the Sun’s path (makes sense, doesn’t it?).

Another fact of the solar system is that everything reflects the Sun’s light to some extent. Again, this makes sense, but a lot of people don’t realize it. Take moonlight, for instance. The moon doesn’t “shine.” What we call “moonlight” is simply reflected sunlight.

Orbiting the Sun with the big planets and asteroids are billions of tons of microscopic rock and dust. Like everything else, this stuff orbits in the ecliptic. And, like everything else, it reflects light. Not enough to see directly, but when you look through a lot of it, the collective light adds up to a faint glow that is visible.

So, what does all this have to do with the month of October?

Because the Earth’s axis is tilted 23.5 degrees, then the ecliptic is tilted by the same amount with respect to the equator. It intersects the celestial equator at two points, which we call the equinoxes. Therefore, near the equinoxes (for example, in October) that line (the ecliptic) stands almost perpendicular to the horizon.

This alignment means that the faint glow of all the solar system’s dust is most easily visible, rising straight up from the horizon. Astronomers call this the Zodiacal Light (named for the group of constellations the ecliptic appears to travel through). Ancient mariners called it the False Dawn.

From a dark sky site, with no Moon in the sky to wash the darkness away, the zodiacal light can be seen about two hours before morning twilight as a large, cone-shaped glow standing straight up in the eastern sky. This month, the mornings surrounding Friday, the 20th, are the best ones to try seeing the elusive zodiacal light.

Coincidentally, that same night is the peak of the Orionid meteor shower, our annual gift from Comet Halley. Almost all meteor showers are gifts from a single comet. As a comet orbits the Sun, it leaves behind parts of itself, like a boat that’s falling apart as it sails onward, leaving bits and pieces of itself in its wake. Along comes the Earth, on a slightly different – but still intersecting – path, and plows through this debris field left by the comet. When the Earth smashes through the field, those little pieces of comet (each of which is usually about the size of a Rice Krispy) are vaporized by our atmosphere, and seen as meteors. Some comets leave very thick debris fields, and we have lots of meteors. Some leave very sparse fields, and only few shooting stars can be seen.

Comet Halley came through in 1986, and left behind an “average” debris trail. That translates to about 20 meteors per hour at best, right before sunrise (never sunset) on the 21st. Why meteor showers are always best before dawn is a topic for a future column! But to give you a hint, consider the following questions: When you drive in a snowstorm, does your front windshield get hit by more snowflakes than your rear windshield? Why? How does that apply to Earth plowing through a cometary debris field? And how does “sunset” and “dawn” apply in that analogy?

What’s Old
Believe it or not, there is only ONE Messier object visible in the month of October between R.A.: 22h and 24h. It is the open cluster M-52, located in Cassiopeia. M-52 has a rough triangular shape, with a yellow-orange star at its apex that presents a beautiful color contrast with the other field stars in the cluster. At a declination of +61 degrees, M-52 will be close to zenith at local midnight—an angle that is certainly annoying for you Dobsonian users! The cluster is about 15 minutes of arc, so use low power eyepieces. It looks fantastic in binoculars, too.

There are a few NGC objects of note, however. Try for the “Blue Snowball” in Andromeda, NGC-7662. It’s about half the size of the more famous M-51, and located about 10 degrees or so west of the Andromeda galaxy.

One object I love to look for is NGC-7331, a spiral galaxy in Pegasus. When looking at this galaxy, note all of the fainter smudges and “stars” in the background—most of them are galaxies as well!

Glorious image of NGC 7331 by Bob and Janice Fera.

NGC-7317, 18,19, and 20 are just a half-degree SSW of 7331. These are better known by the name “Stephen’s Quintet”

If you happen to be under extremely dark skies this month, you might try for NGC-7293, the “Helix Nebula” in Aquarius. Using filters will make this very large planetary a cinch to see. I recommend you try to see it without filters first, using binoculars. If you see a patch of sky that’s just a tad brighter than the sky background, you’ve nailed it.

What’s New

September begins the prime stargazing season for most northern hemisphere observers. The equinox occurs later this month, after which the nights will be longer than the days (finally!). The weather patterns calm down, the atmosphere steadies, and here in the States, the air starts coming down from Canada, rather than from the tropical Gulf. The dry, steady air brings a tranquility to the season that is perfect for stargazing.

On the 15th, the Moon will be at its highest in the sky in over a century for those in the northern hemisphere. (For those in the southern hemisphere, the Moon will be unusually low in the sky.) Here’s an article by J.E. Brown that does an excellent job of explaining why. Don’t look for it after sunset – it will be visible in the early morning sky.

There’s a lack of notable activity going on in the solar system this month. Jupiter continues to dominate the evening sky after sunset. If you are awake before dawn, you’ll have a chance to see a blazing Venus sinking into the glare of sunrise each day. Saturn has become an early morning object, and is preparing itself for another great wintertime apparition.

But the story continues to be the late summer’s Milky Way, hissing like a puff of steam from the teapot-shaped constellation Sagittarius. There’s nothing quite like taking a pair of binoculars (or a wide-field, low-power telescope), aiming at the teapot’s “spout,” and slowly moving upwards. Billions of stars are visible even in modest-sized binoculars, spread across the field like a fine ash. Here and there, some of the ash clumps into star clusters; and occasionally a dark nebula creates a river of blackness through the field.

What’s Old

There are only nine Messier objects near the meridian around local midnight this month. One of these, M-73 (pictured left), is a grouping of four Y-shaped stars in Aquarius. Cygnus features the two open clusters M-39 and M-29. Both are rather loose and veiled within the billowing star clouds of the Milky Way. M-39 is close—only 825 light years (ly) distant—and spans a large area of sky, almost as much as the Moon. M-29 is much, much farther at 4000 ly, with a diameter of a mere 7 arcminutes.

Four-thousand light years seems fairly distant until you point a scope on the remaining M-objects, which are all globular clusters. The closest of the group is M-30 in Capricorn, shining at a distance of 41,000 ly. Next is the very famous M-15 (pictured right) in Pegasus, which is 49,500 ly away. As we reach 55,000 ly, we pass M-2 in Aquarius. Staying in that same constellation, there is M-72, and its remoteness of 62,000 ly makes it intrinsically dimmer. The record holder for these remaining few globulars, however, is M-75 in southern Sagittarius. The light from the stars within this cluster left a whopping 78,000 years ago!

Other deep sky objects to hunt for are the planetary nebulae NGC-7026, 7027, and 7008 in Cygnus, and the Saturn Nebula in Aquarius.

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Funny stuff.

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