Astronomy.com blog : planets

Busting astronomy myths

Michael Bakich — Mon, 16 Nov 2009 19:22:00 GMT

As the editorial staff of the world’s best-selling astronomy publication, we get a lot of e-mails. Some suggest story ideas, some praise a column, feature, or image, and many ask questions.

Lately, lots of e-mail writers have enquired about astronomy-related stories they’ve heard on the radio or television or read on the Internet. For example, “Is it true that Mars will appear as large as the Full Moon to the naked eye in August?” or, “I’ve heard astronauts can see the Great Wall of China from the Moon.”

Both of these are myths. And, although we answer all e-mails sent to us, at times it may take a while for us to get back to you. So, to provide even speedier replies, we’ve set up a special area called "Astronomy Myths" in the "Welcome to Astronomy" section of our web site, Astronomy.com, to which we can direct questioners.

Once there, you’ll find detailed explanations of myths like “There’s no gravity in space” and “The Moon doesn’t spin.” And, oh yes, we do address the one about the world ending in 2012.

This is the way the world ends

Bill Andrews — Mon, 16 Nov 2009 17:42:00 GMT

This isn’t going to happen in 2012! Baseless theories, like a proposed planetary alignment on the scale of this photo illustration, have led many to fear the year 2012 needlessly. Lunar and Planetary Laboratory (NASA) photo

Rejoice, for the end is nigh. Not of the actual world, of course, but of 2012’s marketing campaign.

As you are no doubt aware, Roland Emmerich’s end-of-the-world epic, 2012, opened this weekend. As in Emmerich’s previous movies (Independence Day, Godzilla, The Day After Tomorrow), 2012 features mass destruction and plucky everyday people who become heroes. But, whereas the destruction was somewhat limited before — even the aliens focused on large cities — the entire world now lies on the chopping block.

Infinitely worse, though, pseudo-scientific ads and posters featuring a fictional (but very realistic) Institute for Human Continuity were part of the movie’s ad campaign, making people think the world really might end in 2012. And being in charge of correspondence here at Astronomy magazine, I bore the brunt of many letters asking about the supposed planetary alignment, or the phantom Planet X/Nibiru impact, or why we help NASA cover up the facts that point to planetary destruction. This meant the movie 2012 went from “seems dumb, but it might be fun to watch” to “I hate this movie” pretty quickly for me.

And apparently I’m not the only one. NASA set up a web page explaining, “Nothing bad will happen to the Earth in 2012.” While that sure is nice of them, isn’t it a little sad that NASA has to go on record and officially let people know these random Internet rumors and hoaxes aren’t true? Do people really need to be reminded that what happens in movies isn’t necessarily true?

So, basically I want to know: Did you see or do you plan on seeing 2012? Given my personal animosity, you may be able to predict my response, but the reviews aren’t making it sound that great either. One thing’s for sure, though. Once the movie’s been out a while, the ads will stop, and my life will get a lot easier. For about a year and a half, anyway.

Astronomy contributing editor attends White House star party

Matt Quandt — Fri, 09 Oct 2009 14:53:00 GMT

Special guest blog from Contributing Editor Martin Ratcliffe

President Barack Obama and his family joined 150 school children, dozens of amateur astronomers, professional scientists, and education and public outreach professionals Wednesday night during the Star Party at the White House. And how cool was this? “Cool” doesn’t even come close. I was lucky to be a part of the exciting events running one of the planetarium domes set up on the South Lawn of the White House.

Thirty of us spent most of the day setting up for the 2-hour evening event. And weather cooperated except for some strong winds during the daytime. A more perfect night could not have been achieved, with crystal clear skies of the nation’s capital.

Crater impact experiments and samples of Moon rock provided great activities to highlight today’s LCROSS impact on the Moon. Many telescopes ranging from 2 to 18 inches were available. Dr. Stephen Pompea demonstrated the 2-inch Galileoscope, and he showed me a great view of Jupiter’s moons. Dean Koenig of the Starizona company brought his amazing f/2 Fastar imaging system, which showed one group of children a quick image of the Andromeda Galaxy (M31) right after they had seen M31 in my planetarium dome. The teacher had asked if they could see M31 directly, and I suggested they visit the Fastar scope and ask for a CCD image, and they saw it in all its glorious detail.

This unique night included special guests such as astronaut John Grunsfeld (Hubble servicing mission), Sally Ride (first American woman in space), Buzz Aldrin (second man on the Moon), and Charlie Bolden (NASA administrator, who helped launch Hubble from the cargo bay of the space shuttle).

White House staffers said presidents are not known to spend much time at events on the South Lawn. The Obamas spent more than an hour at the event, and the family showed a great deal of interest. They looked through telescopes at Jupiter and the Moon, and after his formal remarks, the president and first lady viewed the famous Double-Double in Lyra. As readers of Astronomy magazine know well, these objects are star party favorites.

Two planetarium domes were there, one supplied by Sky-Skan, Inc., a major digital planetarium supplier, and a second from Goddard Space Flight Center. The Obama family, daughters included, climbed into the Sky-Skan dome along with 25 school children, and they spent 10 minutes flying around the solar system and asked interesting questions. With two girls of my own, I know how important it is to expose your kids to science, and astronomy is a great way to do it. It was a great privilege to present the planetarium show for the president’s family, huddled as we were inside the 25-foot diameter dome.

Providing a cosmic perspective to young children is fun, engaging, and important, and bringing astronomy to the nation’s attention for a brief moment Wednesday night was the highlight of nearly 6 months of behind-the-scenes work by NASA educators, who, following encouragement from IYA organizers and many individuals to host a star party at the White House, were called in by the White House to plan the event.

Martin Ratcliffe, in addition to being a contributing editor to Astronomy magazine, is also Director of Professional Development for Sky-Skan.

Division of Planetary Sciences meeting, Thursday recap

Liz Kruesi — Thu, 08 Oct 2009 21:45:00 GMT

Thursday was a short day at the conference. I had to check out of the hotel in the late morning, so I had time only to jump between two sessions (another exoplanet one, and one about near-Earth asteroids [NEAs]).

Editor's note: Liz is posting updates regularly from DPS09 to Twitter.com/AstronomyMag.

The exoplanet session focused on what I’ve noticed to be an extremely popular topic here at the conference — modeling exoplanet atmospheres. That’s good to hear, because a near future issue of Astronomy will feature an article about this. So make sure to keep an eye out for it!

I then headed over to the NEA session. This was interesting stuff. I haven’t heard much about Apophis lately … until these presentations. Apophis is the asteroid that was in the news about 5 years ago because astronomers predicted there was a chance as high as 1 in 37 of it slamming into Earth in 2029. Scientists quickly revised that prediction … but not after the public – and the media – freaked out about it. Now we know there’s a 0 percent chance the asteroid will hit our home planet in 2029.

There is a chance, however, that it could pass through a gravitational “keyhole.” This is a small window (about 600 meters in diameter) where the gravitational forces would set up a collision with Earth. But the chance of such a collision has now been downgraded to just 1 in 250,000 in 2036, said David Tholen of the University of Hawaii and Steven Chesley of Jet Propulsion Laboratory today at DPS. Following additional observations and modeling, Tholen’s group estimates Apophis could pass through another keyhole in 2067, which would send it on a 2068 collision course with Earth. This keyhole, however, is just 2m in diameter … that’s pretty tiny. The chance of impact is even smaller than 2036’s chances — about 1 in 333,000.

It sounds like we’re pretty safe from Apophis, but we’ll need more observations to determine whether this fact holds true for all the other NEAs out there. Upcoming large-scale surveys should provide some of these much-needed observations.

All right, I’m off to explore Puerto Rico’s El Yunque rainforest and bioluminescence bay. Then the Arecibo Observatory on Saturday.

Previous post: Wednesday recap

Division of Planetary Sciences meeting, Wednesday recap

Liz Kruesi — Thu, 08 Oct 2009 20:20:00 GMT

I started off Wednesday at a lunar science session where presenters focused on results from the Japanese Kaguya mission and the Lunar Reconnaissance Orbiter (LRO). Robert Reedy of the Planetary Science Institute discussed Kaguya maps of the Moon. The probe measured gamma rays to study the distribution of elements, and it produced the first global uranium map of the Moon.

Editor's note: Liz is posting updates regularly from DPS09 to Twitter.com/AstronomyMag.

A few presenters talked about early LRO results — that mission is already chugging out some great science. And it’s only been taking data for (depending on the instrument) 1-3 months. Benjamin Greenhagen of the Jet Propulsion Laboratory presented information about the Diviner instrument, which measures surface temperatures. Early findings with this instrument were actually in the news a few weeks ago: Scientists used this device to discover portions of the permanently shadowed regions at the Moon’s south polar region are around 35 kelvin. That means these regions are looking like the coldest areas in the solar system. Greenhagen added that we’re approaching lunar summer now, so it appears these regions are warming a small amount, but they’re still under 50 K. That’s cold.

Next I headed over to a near-Earth asteroid (NEA) session. Mike Nolan of Arecibo Observatory talked about the diversity among NEAs, which I found extremely informative. Astronomers split NEAs into the following categories: irregular bodies (potato-like), spheroids, binaries, and bars (elongated asteroids, termed “bifurcated asteroids”). The bifurcated ones look like someone smashed two play-doh spheres together. As Nolan is also the observatory director, he touched on how important radar observations of NEAs are; this is one type of research astronomers use Arecibo for. He ended his talk on a fairly sad note regarding funding for the next few years. It sounds like they have significantly less funding starting in 2011.

After a quick lunch, I sat in on another exoplanet session. This one focused on transiting exoplanets — those that pass in front of their stars from our point of view — and observing and modeling some of those planets’ atmospheres. While I already knew about this method (characterizing some extrasolar planet atmospheres), it was interesting to hear more about how the researchers do this. It sounds like this area will continue to grow … just like the entire field of exoplanet research.

To end the day, I walked through the exhibit hall and looked over some of the posters. Tomorrow I’ll bounce around between another exoplanet session and an asteroid session. Then I’m off for a day to explore the natural side of Puerto Rico (I’ll do a bit of kayaking and hiking).

On Saturday I head to Arecibo Observatory to tour the huge instrument before flying back to cold Wisconsin.

Previous post: Tuesday recap

Division of Planetary Sciences meeting, Tuesday recap

Liz Kruesi — Wed, 07 Oct 2009 19:10:00 GMT

One thing I’ve noticed at thisi year’s Division of Planetary Sciences meeting is how well members of the planetary science community support each other. Often when asking a question regarding a talk, the questioner starts out with “great talk.” It’s refreshing to see. There’s a lot of competition in the sciences (so much of a career rides on how many papers one publishes), but clearly there’s a lot of collaboration as well.

Editor's note: Liz is posting updates regularly from DPS09 to Twitter.com/AstronomyMag.

OK, back to the updates from the DPS meeting. Tuesday morning began with a few awards. First up was the first-ever Jonathan Eberhart Planetary Sciences Journalism Award, presented to Sky & Telescope Senior Contributing Editor J. Kelly Beatty. After he received his award, Clark Chapman of the Southwest Research Institute discussed Mercury and the three MESSENGER flybys. The September 29 flyby showed additional examples of volcanism, according to Chapman. The probe is scheduled to enter its science orbit around Mercury March 18, 2011, and promises more discoveries.

The next award — the Urey Prize — went to Sarah Stewart of Harvard University, for her research of impacts onto icy bodies. Then the DPS awarded the Kuiper Prize to Tobias Owen of the University of Hawaii at Monoa “for his outstanding contributions to the field of planetary science.”

Owen, “one of the fathers of the Cassini mission,” still works on the project. He gave a great lecture — it had spots of humor and covered a fairly broad topic (so that even I, with my little planetary science expertise, understood the majority of it). It sounds like he has impacted many areas in planetary science. It was a pleasure sitting in on his talk.

At lunch I tried driving to a grocery store only to discover that none of the streets in Fajardo, Puerto Rico, is labeled. Mission failed.

The second half of the day switched gears and was filled with science sessions, so I tried to jump around to a few different ones.

First I attended a session about irregular satellite debris belts. Anne Verbiscer of the University of Virginia announced her team’s discovery of an enormous dust ring around Saturn. Douglas Hamilton of the University of Maryland followed with additional details. This ring is the largest known planetary ring in the solar system. It’s some 40 times Saturn’s radius (Rsat) high. Its inner edge starts around 128 Rsat out from Saturn and extends to 207 Rsat. The ring seems to be inclined 27 degrees to Saturn’s equatorial plane.

The team observed this huge ring with the Spitzer Space Telescope. Saturn’s irregular satellite, Phoebe, is within the ring. The team described how impacts with Phoebe produced debris that remains in a thick disk around the satellite’s orbit, therefore creating this huge ring. Hamilton explained that if you were standing within the ring, the density is such that you’d be hit by a particle about once per minute — that’s a pretty low density. The October 7 issue of Nature includes the team’s study.

After sitting in on a few presentations in a session about Titan’s surface, I stopped by a science discussion about the atmospheres of jovian planets. In this presentation, Teresa Del Rio Gaztelurrutia of the Universidad del Pais in Vasco, Spain, described a long-lived cyclone in Saturn’s atmosphere. This cyclone has been around for at least 4 years (Cassini instruments have observed it from June 2004 through May 2008).

Wednesday looks like another jam-packed day. I’m definitely looking forward to wandering through the exhibit hall to view the posters.

Previous post: Monday recap

Division of Planetary Sciences meeting, Monday recap

Liz Kruesi — Tue, 06 Oct 2009 18:43:00 GMT

Monday was my first day at the 2009 Division of Planetary Sciences meeting in Puerto Rico. Unfortunately, I was off to a late start because of one of the worst migraines of my life. But I did get to the afternoon science sessions.

Editor's note: Liz is posting updates regularly from DPS09 to Twitter.com/AstronomyMag.

I spent the early afternoon at the Titan science session. Nine scientists talked about the saturnian satellite’s atmosphere and geological features. William Smythe of the Jet Propulsion Laboratory discussed his team’s deduction that transient features seen on Titan are likely patches of pure ammonia frost. These features are too close to the ground to be clouds, so they’re either ground fog or surface coating. When scientists look at the features’ spectral signatures, they most closely match ammonia.

Ralph Lorenz of the Johns Hopkins University Applied Physics Laboratory discussed his team’s (and other groups’) observations of Titan’s brightness and how it changes over time. Lorenz summed up almost 40 years of observations (starting in the early 1970s). Various astronomers started observing Titan in 1972 and saw that it was brightening … but then it started darkening.

Since then, astronomers have determined that the northern hemisphere is some 20 percent darker than the southern. Seasonal changes could explain the observed brightness changes, but this doesn’t explain the full amplitude of brightness changes. Plus, the cycle isn’t perfectly symmetric, and right now Titan is darker than previously recorded. Why could this be? The Lorenz group thinks there is something going on with Titan’s haze layers, which could be affecting the observed brightness.

In the late afternoon I sat in on a session about rocky extrasolar planets. After quite a few technical problems, the program started. This session was filled with what to look for when trying to detect earthlike planets and life on those planets. A few talks focused on what our Earth looks like from a distance (this is data that the EPOXI mission was able to collect), and therefore what we should look for in similar planets.

Editor’s note: EPOXI is a combination of the names for two extended mission components: a search for extrasolar planets during the cruise to Hartley 2, called Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact eXtended Investigation (DIXI).

Carolyn Crow of the University of Maryland talked about EPOXI observations of Earth and the Moon using seven spectral filters. Crow and colleagues compared those Earth observations with spectra of the other planets, and found that in low resolutions Earth is brighter than the others with certain filters.

Eliza Miller-Ricci of Harvard University discussed a possible way to directly image terrestrial planets. Back in November 2008, astronomers announced that they had directly imaged gas giant planets orbiting their stars in two systems. However, gas giant planets hold onto their initial heat (from formation) for longer than rocky planets, so astronomers have a better chance of finding a young gas giant planet than a rocky one. Miller-Ricci (and colleagues) recommended that, instead, astronomers might want to search for the afterglow of a young super-Earth collision. (As we know from the formation of Earth, a Mars-sized object initially slammed into the forming Earth. Such collisions are likely typical in young solar systems.)

The surfaces of these super-Earths will be hot initially (1,500 to 4,000 K) and cool in free space within about 100,000 years. However, if the object has a thick atmosphere, it takes 1 to 10 million years to cool. So maybe 10 percent of young stars have hot super-Earth afterglows at any given time.

There was a lot of information that came out of Monday’s sessions. Tuesday should be similar, with the addition of three major talks in the morning, given by three scientists awarded DPS prizes for their research.

On the road: The 2009 Division of Planetary Sciences meeting

Liz Kruesi — Mon, 05 Oct 2009 19:13:00 GMT

This week I’m in Fajardo, Puerto Rico, at the Division of Planetary Sciences meeting. I’ll be blogging daily and posting updates regularly to our Twitter, Facebook, and MySpace pages.

Then on Saturday I’ll have the opportunity to tour Arecibo Observatory, which is a once-in-a-lifetime experience. It should be a good week, filled with lots of news, science updates, and humid temperatures.

Haumea’s newly discovered spot

Bill Andrews — Wed, 16 Sep 2009 17:02:00 GMT

Dwarf planet Haumea, out in the Kuiper Belt past Pluto and Eris, just got its big break. The formerly little-known object hit the big time Wednesday at the European Planetary Science Congress when Pedro Lacerda announced a dark red spot on its surface.

And, not to copycat Jupiter and Neptune, Haumea’s big spot (pictured in the computer model still at right) probably isn’t a giant storm. While the extreme distance between the object and us makes any conclusions uncertain, the current interpretations make the spot out to be an area richer in minerals and organic compounds or one with a higher fraction of crystalline ice. A massive impact may have caused it, but that’s only speculation.

Scientists discovered the spot by investigating changes in the object’s brightness as it rotated. And with Haumea’s ridiculously fast rotation time, where one haumean day lasts less than 4 Earth hours, that change in brightness was all the more noticeable. In fact, Haumea’s rapid rotation deforms the dwarf planet into an ovaloid, and not spherical, shape. Some theories pin the cause of this, the solar system’s fastest rotation, on a massive impact, but again, it’s just a guess.

It’s astounding to me how much we can figure out about something so far away that it’s essentially a dim point of light in the sky. But because we know so much about light and how it interacts with everything else, even that dim point can tell us a lot. And with plans to study Haumea next year with the European Southern Observatory’s Very Large Telescope, the dwarf planet could be in front of the spotlight for a long time.

So what do you think? Impressed by the reach of our knowledge? Has Haumea always been a big (Hollywood-type) star for you? Or are you unimpressed with what’s just an ice-covered, roughly football-shaped rock in the distance?

Photo credit: P Lacerda

A terrific Saturn animation

Michael Bakich — Wed, 02 Sep 2009 18:54:00 GMT

Lunar and planetary imager Alan Friedman of Buffalo, New York, just sent me a terrific animation he made of Saturn. And it took him a while to do it. Friedman combined 6 years of Saturn observations to create the animation. It shows how the plane of the planet’s ring system has changed during that time as viewed from Earth.

The animation’s final frame is not an image Friedman captured at the telescope. He assembled that frame from earlier 2009 observations to display how the planet will appear September 4, 2009, when the rings will lie edge-on to our line of sight.

On that date, only 11° separates Saturn and the Sun, and the planet will be only 5° above the horizon at sunset. That situation makes Saturn almost impossible to observe.

In the fall of 2009, Saturn will emerge from the Sun’s glare in the early morning sky. At that time, observers on Earth will have their first glimpses of its north pole in 14 years.

Friedman used a 10-inch Astro-Physics Maksutov-Cassegrain telescope and an Imaging Source DMK21AF04 CCD camera to record the images. You can see the individual photographs in the second image.

See additional images of Saturn in our Online Reader Gallery.