Depiction of a major alignment of
the five visible planets in 1059 BCE.

Photo By Ben Burress

There are some pretty good “lineups” coming soon to skies above you.

First of all, “lineups,” or alignments, go on in the heavens all the time, though most often they are alignments of objects too faint to easily notice, if at all. With that said, this summer holds some significant alignments of some of the brightest objects in the sky.

First on my hit list is the upcoming Saturn-Mars “near-miss”. Though these two planets are not coming physically close to each other (the closest actual distance they come to each other is about 750 million miles), they will align so closely along the same line of sight that on July 11^th they will appear only ¾ of a degree apart-that’s not much greater than the width of a Full Moon. The best time to see this pairing is after sunset on the evenings of July 10, 11, and 12, over the western horizon.

The next big ticket alignment is on August 1^st, when the Moon and the Sun occupy the same spot in the sky-the event we call a Total Solar Eclipse. As it happens, we won’t be able to see this eclipse directly from the United States, as it will only be visible in Asia. However, NASA will be broadcasting live coverage of the eclipse from Northern China. We’ll be showing NASA’s broadcast in our planetarium at Chabot Space and Science Center, in case you’d care to come up and enjoy the spectacle. Don’t let the fact that the live event goes on around 4:00 AM keep you away…it’s worth getting up for!

A bit further out on the calendar is the September alignment of three planets: Venus, Mars, and Mercury. In the dusky twilight of mid-September evenings the three will be gathering. The closest grouping of the trio is on September 11^th, when they will be within about three degrees of each other-close enough that you can just about cover all three with your thumb. Mercury and Mars won’t be very bright in the twilight-but Venus, bright enough to spot easily, can help guide your eye to the other two. Using a pair of binoculars will help a lot-but make sure you don’t point them that way until after the Sun sets….

In ancient times (and in some cases not so ancient times), different cultures around the world have viewed alignments like these in different ways. Eclipses-both solar and lunar-were regarded by many cultures as bad omens, or bad occurrences (such as the Sun being devoured by a celestial animal-dragon, dog or other-in the case of a solar eclipse).

Planetary alignments were also given special consideration, sometimes being regarded as auspicious (for good or bad-usually the latter). One major alignment of the five visible planets (February 26, 1953 BCE) was believed to have “mandated” the creation of the Hsia Dynasty in China-the first great Chinese Dynasty. (Then, four centuries later, Mars, Mercury, Jupiter and Saturn apparently conspired to bring down that same dynasty-at least, their alignment on December 20, 1576 BCE was interpreted as an indicator of the dynasty’s corruption, and it was overthrown by a revolt of believers…).

However you regard the lining up of celestial bodies (astronomically, astrologically, or aesthetically), these alignments are pleasing to watch, and times to reflect upon the constant and cyclic movement among the heavens. Enjoy….

School groups tour the Oakland Schools Science Fair
projects at Chabot. Ben Burress, Chabot Space & Science CenterIt’s the time of year again that I get a chance to peruse what our scientific-minded youth are thinking on questions of the physical world and universe around us: Oakland Unified School District Science Faire!

The science projects of students from a range of schools in Oakland are on display at Chabot Space & Science Center for a couple of days-a long-time tradition I know, because when I was in elementary school (Glenview Elementary in Oakland) I participated in the Science Faire every year and wound up with my First Grade project (Which Straw Works Best-longer or shorter?) on display at Chabot Observatory on Mountain Blvd.

So I went out into our halls to browse the rows of free-standing cardboard displays (all pre-fabbed display boards; in my day we’d make our own from boxes, staples, and glue!) to see what today’s young minds are thinking about science. In particular, I was looking for any that dealt with astronomy.

As usual, I saw a range of science topics, presentations styles, decoration, and grade levels. I saw the cadre of “standard” science projects that get done every year (the tabletop volcano, the floating egg, the electric potato, and the like).

I also saw some that I’d not seen before. There was one where the question asked was who has more germs, boys or girls? The experimenter took swab samples from behind the ears and from the hands of the students in her fourth grade class and grew germ cultures, which were all displayed before the presentation board in little plastic Petri dishes. What was the result? Do you want to know? Well, by this experiment at least, the girls won over the boys in having more germs from both sample sites….

But what of the astronomy? In all of the couple hundred project displays, only three of them were astronomy projects. This doesn’t surprise me too much, since astronomy is for the most part an observational, not experimental, science and doesn’t lend itself to the kinds of things kids like to get their hands into. And of my own elementary school science faire projects, not one of them dealt with astronomy, so I really can’t complain!

What were they? One dealt with observations of Moon phases, asking the question is there a pattern to the way in which the Moon’s shape changes from day to day. One asked why do the planets of the Solar System take different periods of time to orbit the Sun, and why do they have different temperatures. Finally, one asked the ultimate Inconvenient Truth sort of question: What would happen to Earth if the Sun suddenly turned off? (That would be inconvenient!) The answer to that one was, not long, since just about everything we do requires energy derived ultimately from the Sun.

The results of my own observation project, walking down the halls of Chabot and seeing what’s up in the minds of our youth, was a happy success: the curiosity and scientific enthusiasm of our budding scientists appears to be alive and well.

Illustration of a blast of solar wind impacting
Earth’s protective magnetic field. Credit: NASABreathe in, exhale. Feel the air in your mouth, windpipe, and lungs. That’s a sample of Earth’s atmosphere: the thin layer of gases enveloping our planet.

Did you know that the Sun also has an atmosphere, and that the Earth is inside it? In fact, the Sun’s envelope of gases extends well beyond the orbit of Pluto, out to the regions of the solar system where the 3-decade-old Voyager spacecraft are only now reaching.

“Space weather” refers to the conditions in space caused by the outflow of electrically charged gases (plasma) coming from the Sun—what we call the “solar wind.” The term “space weather” may conjure images of cosmic tornadoes, astral lightning bursts, and some Star Trek version of a galactic hurricane– but actual space weather is nothing so Earthly and familiar.

First of all, the “air” in space is nothing like the atmosphere we draw our breath from. Earth air, at the surface, is made of nitrogen, oxygen, argon, carbon dioxide, water vapor, and other trace elements, and is relatively dense. “Space air” is mostly hydrogen– ionized hydrogen at that (meaning stripped of its electrons and so electrically charged; the separated electrons are also blowing along in the solar wind).

Second, the gases of the solar wind are extremely rarified. Despite the talk of a solar atmosphere, solar wind, and space weather, space within the solar system is still almost a complete vacuum. At Earth’s distance from the Sun, the average density of the solar wind is somewhere between 6 and 9 atoms (mostly hydrogen) per cubic centimeter. If you spread out the gas contained in an ordinary party balloon to this same thinness, it would fill a volume of space over 10 miles across!

Third, the solar wind, for all its sparseness, blows fast! Depending on conditions of space weather, the flow of solar wind past the Earth can speed along anywhere from 200 to 900 kilometers per second! Earth’s fastest winds slug along at only a few hundred kilometers per HOUR.

So how does space weather—the changing conditions of the solar wind—affect us on Earth? How might you, personally, have experienced, directly or indirectly, the effects of the Sun’s gentle breeze?

The most familiar phenomenon caused by space weather is Earth’s beautiful auroras —the northern and southern lights. Interactions between the solar wind and Earth’s magnetic field and electrically charged particles trapped in it excite atoms in the upper atmosphere to emit light. And it’s not just a softly glowing night light: the most powerful auroras can generate up to a trillion Watts of power!

Solar wind “storms” can not only produce more active auroras, but can cause fluctuations in Earth’s magnetic field whose effects can be felt on the ground. These “geomagnetic storms” usually pass unnoticed, perhaps causing a tiny change in the direction that compass needles point– but have also been known to overload electrical power grids and cause blackouts.

In the space around Earth, solar storms have been known to damage or disable satellites, and can put unprotected astronauts at risk. Space walks on the International Space Station are scheduled for times when space weather is - so to speak -”sunny and calm.”

Thinking about space weather on Earth might seem like worrying over Atlantic hurricanes here in the Bay Area—but with more and more human activity taking place beyond the confines of our atmosphere, this is a very real and vital concern, and is taken very seriously.

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

It’s approaching that time of year again: Spring Equinox. The blaze in my home’s interior hallway has been signaling this for the last week.

The shadow of Chabot’s “solar clock” at noon
on the equinox produces a pattern of solid green
straddling the gnomonI noticed late in the afternoon a couple days ago that the windowless hallway where we hang all of our family photos was afire in a shaft of bright sunlight, entering a window in the adjacent bedroom. Only around Equinox (Spring or Fall), when the Sun sets about directly west, does this happen in my house. The rest of the year the Sun sets too far north or south for this window-and-hallway alignment to take place. It’s a striking event because for only a few days of the year my normally dark hallway explodes with radiance.

Ancient cultures all around the world made use of the changing rise and set position of the Sun to track the seasons, and either observed special alignments of sunlight and shadow with geographical features, or built structures that made the special alignments. Stonehenge is one famous example, but there are plenty of other seasonal observatories in just about every part of the world.

Unlike the more distant stars in the sky, which always rise and set at the same points on the horizon, the Sun (a star too, of course) wanders northward and southward in the sky throughout the year, and so its rise and set points migrate. On the Equinoxes the Sun rises directly at the east point on the horizon and sets directly at the west point-but at Summer Solstice in the Bay Area it rises a full 30 degrees to the north, and at Winter Solstice 30 degrees to the south.

The reason for the Sun’s annual wandering comes from the tilt of Earth’s rotational axis with its orbit around the Sun. At our (Northern Hemisphere) Summer Solstice, our hemisphere is tipped toward the Sun and the Sun appears at its most northerly point in the sky; we receive more hours of sunlight and more direct rays from the Sun-so it’s warmer. Winter Solstice is opposite, with our hemisphere tipped away and the Sun and the Sun farthest to the south, making for shorter hours of daylight and less direct solar rays–and so it’s colder.

Equinox is a middle point between solstices: the Sun is poised between the northern and southern extreme points of the solstices-positioned directly over Earth’s equator-and the hours of daylight and night are about equal.

Does your home or place of work function as a solar seasonal calendar, as mine does? Is there a special time of year when you notice a striking pattern of light and shadow, a special alignment of walls, windows, doors, or other features? From the location of Chabot Space & Science Center, at equinox the Sun sets directly on the Golden Gate Bridge… .

If you have noticed something like this, then you’ve experienced what many ancient peoples noticed about the seasonal changing of the Sun. Their observations led them to understanding, or at least making use of, the cycle of the Earth revolving about the Sun to establish the earliest calendar systems.

Take a look and see what you notice, especially around Equinox (March 19, Pacific Time-March 20 GMT).

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

The original Oakland Observatory in the 1880’s,
at Lafayette Square in Oakland. Credit: Chabot Space
& Science Center archives.This year marks an anniversary for the astronomical heritage of Oakland and the San Francisco Bay Area: Chabot Observatory turns 125!

Originally established as the Oakland Observatory in 1883, the facility was a unique creature from the very beginning. Conceived by then Oakland Public Schools Superintendent Jewett Gilson, who was inspired by a school observatory he saw in Philadelphia, the observatory was created for use by Oakland schools and the general public at large.

Gilson looked for, and eventually found, a donor to fund the observatory project: Anthony Chabot, a wealthy entrepreneur and philanthropist who made his fortune building municipal water systems in the Bay Area– including Lake Temescal and Lake Chabot. Anthony Chabot stipulated as part of his original $3,000 gift that the telescope shall forever be available for public observation at not cost– a tradition that continues today.

Chabot didn’t want the observatory to be named for him, so in its earliest years it was called the Oakland Observatory. The public, as the story goes, insisted on calling it Chabot Observatory in gratitude for the gift– and eventually the name was made official.

The original location for the observatory and its 8-inch Alvan Clarke and Sons telescope (”Leah”) was close to downtown Oakland in Lafayette Square– which today remains a square block of parkland, at 10th and 11th Streets and Martin Luther King Junior Way and Jefferson Street. In those days, 10 or so visitors on any given night would climb the tower-like structure to the telescope dome and peer at the heavens through the high quality instrument. Reservations had to be made in advance– sometimes as long as a month or two.

As Oakland grew, and particularly as it converted its street lighting from gas-powered lamps to electric lights, the necessity of moving the observatory to a darker spot grew. The observatory’s first director, Charles Burckhalter (who is said to have been the first person in Oakland with an astronomical telescope, set up in a backyard observatory at his home on Chester Street), arranged for the relocation. A number of different sites were considered– including a spot near Redwood Peak, the current location of the observatory– but a small hill next to the Mills College campus was finally adopted.

In 1915, Chabot Observatory opened at its new site, along with a new 20-inch Warner and Swasey telescope (”Rachel”), and continued to wow the public with the astronomical vistas it conveyed. In 1923 the directorship passed to Earle Linsley, a Mills College professor, who expanded the reach of the observatory to the public through outreach to schools and the establishment of an amateur astronomy group (today the Eastbay Astronomical Society).

Having visited this Chabot Observatory as a child in the 1960s, I now appreciate how long and distinguished a career those two telescopes spanned. At the time, I had no idea that Leah, even in 1968, was 85 years old-older than my grandparents! Then the observatory was run by the beloved Kingsley Wightman — “Mr. Science” to a generation or two.

It took the moving Earth to relocate the observatory a second time– literally. Because of Chabot Observatory’s location almost directly on top of the Hayward Fault, and the fact that the aging buildings were not quake– safe in the first place, another site had to be found: the present location of Chabot Space & Science Center, adjacent to Redwood Peak.

Happy 125th to Oakland’s special connection with the stars!

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

Extreme close-up of the Sun’s visible surface,
showing ‘bubbling’ cells of convecting gas–each the size of
Northern California. credit: Hinode JAXA/NASA/PPARCBy all accounts, a new cycle-Cycle 24-in solar activity has begun… something you probably didn’t notice since the beginning of a solar cycle is quite subtle….

First things first: what is a solar cycle, and why is this one number 24? You’ve probably heard of sunspots and solar flares and disturbances in radio communications caused by solar activity, but had you noticed NOT hearing much about these things in the last two or three years?

The Sun exhibits a cyclic rise and fall in its level of magnetic activity. Being an enormous ball of roiling, circulating plasma (electrically charged gas), the Sun generates powerful magnetic fields in a way similar to how the circulating electricity in an electromagnet creates one.

Over the course of a solar cycle, the intensity and amount of magnetism generated by the Sun increases, like soup warming up on the stove, reaching a violent climax in which twisting, tangling magnetic fields break loose and release their energy in the form of solar flare explosions, coronal mass ejections, and tremendous heating of the solar atmosphere.

Sunspots are surface features formed by the presence of strong magnetic fields, and in general the number of sunspots that can be seen and counted indicate the level of magnetic activity on the Sun. For 400 years, since Galileo first started counting sunspots through his telescope, observers have kept track of sunspot counts, and over time a pattern in their number emerged. On average, the number of sunspot activity peaks every 11 years at a time called solar maximum.

I remember when I first started working at Chabot Space & Science Center, back in 1999/2000, during the last solar maximum. Using our Sunspotter telescopes on public observing days, in teacher workshops, and in my solar summer camp, we could easily count many sunspots-sometimes as many as 20 or more! Those were the days!

In the past two or three summers, however, it’s a lucky week to spot just a single sunspot! Most of the time, the Sun’s face has been a bland disk with few discernible surface features.

That status quo should start to change, now that we have allegedly reached solar minimum and are stepping onto the uphill slope toward the next maximum, which should happen sometime around 2011 or 2012. If you want to keep tabs on the rising solar activity, and you like lots of graphs and numbers and stuff like that, check out the Solar Cycle 24 website.

Oh, why is this Cycle 24? A 19^th Century astronomer who studied the then newly discovered sunspot cycle, Rudolf Wolf, established the cycle that spanned 1755 to 1766 as Cycle 1…and they’ve been counting up ever since.

But even in this “nap time” of the Sun, today’s modern solar observatories and spacecraft, with their arrays of high-tech cameras and sensors, see plenty on the Sun to keep them busy.

Japan’s Hinode spacecraft, launched in 2006, has returned libraries of amazing pictures and movies of solar flares, activity around sunspots, circulating hot gases, fine details of the life and times of magnetic fields…and all of this during solar minimum! I can’t wait until the Sun really gets going and Hinode becomes like a camera-happy tourist in Tahiti….

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

More than meets the eye: The constellation Orion
in visible light (left) and infrared (right)
Visible light image: Akira Fujii;
Infrared image: Infrared Astronomical SatelliteSome months ago my blog, “SOFIA: Fly By Night,” talked about the up-and-coming astronomy ace of the night skies, SOFIA: the Stratospheric Observatory for Infrared Astronomy–a 2.5 meter infrared telescope built into a Boeing 747 airplane.

SOFIA’s been flying, and is gearing up to begin its first science flights in the not so distant future. SOFIA even put in an appearance in Bay Area skies a couple of weeks ago with a quick visit to NASA/Ames Research Center in Mountain View–then it was off again to its base of operations in the Mojave Desert.

Having worked on SOFIA’s predecessor, the Gerard P. Kuiper Airborne Observatory (KAO), in the last seven years of its operation, I thought I’d focus a bit on the science of airborne infrared astronomy, touching a bit on science done on the KAO over its 21-year career at NASA/Ames.

Why put a telescope on an airplane? Earth’s atmosphere, while transparent to the visible light the human eye can detect, is less so to many other wavelengths of light, including most infrared light. In fact, the water vapor in our atmosphere is pretty much opaque to a wide range of infrared wavelengths.

KAO flew at and altitude of 41,000 feet to get above as much as 99% of Earth’s atmospheric water vapor, giving astronomers a view of the infrared emissions from objects in space almost as if the telescope was out in space.

What’s so interesting about looking at infrared light? Aren’t visible light images taken from ground-based observatories enough?

Apparently not. Visible light is only a tiny fraction of the overall spectrum of electromagnetic radiation (the general term for “light” of all types–including gamma rays, X-rays, ultraviolet light, infrared light, microwaves and radio waves). There is a wealth of information contained in the entire electromagnetic spectrum that is only hinted at in the visible portion.

Visible light in our universe comes mostly from the photospheres of stars, either directly or by being reflected by objects such as dust, planets, comets, and the like; all of the light you see in the sky is starlight, either first hand or second hand.

Infrared light, however, is a lower energy form of electromagnetic radiation, and is emitted by any object or substance that is even slightly warm. So, interstellar clouds of molecules, rings of dust surrounding stars, atmospheres of planets–just about anything, in fact–emits its own infrared light, and observing the infrared emissions from these objects reveals a great deal about them: their chemical composition, their temperatures and densities, their velocities and structure–and a lot more.

One KAO astronomer observed the atmosphere of Venus to measure the relative abundance of hydrogen and deuterium (heavy hydrogen), looking for evidence of past oceans. Another observed Mars, looking for telltales of limestone (a mineral left behind by marine organisms) as evidence of past life on Mars. Others created detailed maps of clouds of complex molecules, probing the composition of the cooler material in our galaxy, as well as other galaxies.

The list goes on, as there’s plenty more cold matter in the universe than hot matter. Cooler matter can be more interesting, too, since complex molecules, like organic compounds and even life, don’t form in the sterile heat of stars.

So where KAO blazed an infrared contrail in the night skies, SOFIA may now follow and carry on the torch of astronomy, on the wing….
Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

latitude: 37.8768, longitude: -122.251

This has been a month of dashed hopes for astronomers around the world. Last month it seemed possible that an asteroid the size of a Boeing 737 jet was due to collide with Mars on January 30. Today that seems far less likely, but, as Amy Standen reports, astronomers consider it a wake up call.
You may listen to the “An Asteroid’s Close Call” radio report online, as well as find additional links and resources.

Amy Standen is a Reporter for QUEST and Radio News at KQED-FM.

latitude: 37.8768, longitude: -122.251

There’s nothing like a trip away from the city lights to remind you just how bad light pollution can be here in the Bay Area.

The Milky Way in the skies of Death Valley’s
Devil’s Racetrack. Credit: Dan Duriscoe, U.S. National
Park ServiceI just got back from my semi-yearly pilgrimage to my favorite spot on Earth: Death Valley National Park. My main reasons for returning to this place again and again have mostly to do with hiking in the stunning natural beauty of the place, reconnecting with good times in my childhood, and reflecting spiritually on life, the Universe, and everything.

But, I can’t go to a place like that and not feel more connected with outer space. Not only is the night sky a celestial spectacle–but it’s darned cold there too, this time of year! Cold, like space. Each turn of the Earth through its own shadow is like a quick dip in the icy pool of space….

After twilight had faded, after the campfire had burned to embers–and as the frigid cold of the desert winter night started seeping through my layers of clothing–I lay down on the picnic bench and raised my binoculars to my eyes…

…and that’s all I had to do. Arcing overhead was the section of the Milky Way around the constellations Cassiopeia, Perseus, Andromeda, Pegasus–a section of the sky rich in a variety of “deep sky” objects (objects typically only visible through binoculars or telescopes).

There was the Double Cluster in Perseus–a pair of “open” clusters of stars.

Open clusters are stars bound together gravitationally, still clinging to each other after their “group infancy” in the gaseous cloud that gave birth to them. Stars in these clusters are young–and because of their youth, open clusters often contain a number of large, bright, blue stars that shine brilliantly–but which have short life spans as stars go, being more prolific hydrogen-burners (gas guzzlers). (In a word, you can’t find an old blue giant star.)

You can’t avoid seeing open clusters in this region; the place is positively littered with them….

This is also where the famous Andromeda Galaxy can be found, in the constellation Andromeda (where else?). What’s special about the Andromeda Galaxy? For one, it’s the closest large galaxy to our own, as well as the most distant object in the Universe that can be seen with the unaided human eye (without telescopic help). Looking at the Andromeda is like looking through a peephole into the realm beyond our Milky Way…

I could go on and on yakking about what I got to see in the clear, dark Death Valley skies last week, so I’ll have to stop myself now. Suffice to say that with a dark sky, a pair of binoculars, and a segment of the Milky Way in view, encountering the celestial wonders of the Universe in a very personal way is like shooting ducks in a barrel.

But don’t let the light polluted skies of the Bay Area stop you from trying it from your own backyard; there’s a lot to behold despite the city lights…

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

Picture of the edge of Victoria Crater superimposed with
image of the rover Opportunity.
Credit: NASA/JPLMars is not only on the horizon, it’s become a sky-high creature of the night…and so, it’s time to blog about the Red Planet once again, and to showcase a few favorite pictures from the veteran robots presently exploring that world.

Mars reaches “opposition” on December 24th. This is the time when Earth crosses directly between the Sun and Mars–in other words, when Mars is at the opposite end of the sky from the Sun and at its closest distance from Earth–this time about 55 million miles. You can see Mars yourself in the evening hours if you face east and look high: it’s that steady, bright, orange dot right between Gemini and Taurus.

So what’s been happening on Mars, exploration-wise? Here’s a quick summary on that score:

NASA’s Mars Exploration Rovers, Spirit and Opportunity, have had their tours of duty extended a fifth time, which should keep the rovers going–their health willing–possibly through 2009. Having landed on Mars in January of 2004 for a nominal 90 day mission, the robot pair has now lasted almost four years.

Spirit, which landed in the huge Gusev Crater, has traveled four and a half miles from its landing point and is now exploring a range of hills on a volcanic plateau. Probably topping the list of scientific evidence it has turned up is that water, in some form, has altered the chemistry in the environment, sometime in the past.

Opportunity, on the opposite side of the planet from Spirit, is currently exploring the half-mile-wide Victoria Crater. Exposed rock layers in the walls of the crater are expected to be an excellent “book” of Mars’ geologic history for Opportunity’s various instruments to read.

In its more than seven mile journey, Opportunity has revealed even stronger evidence that Mars’ distant past may have been warmer and wetter, and that, at least in Opportunity’s neck of the woods (Meridiani Planum), there may have been extended periods with liquid surface water.

The Mars Reconnaissance Orbiter spacecraft, with its array of instruments and super-powerful camera, has produced the most discerning orbital imagery of Mars’ surface to date, giving us aerial views of the Martian deserts, canyons, ice caps, plateaus, volcanoes, craters, drainage channels, sand dunes, and so on, that look like they could have been taken from the window of a small airplane flying at very low altitude.

Even as Spirit and Opportunity send back postcard after postcard from the ground, like a pair of camera-happy tourists, that tantalize us with evidence of possible lakes, seas, and oceans in Mars’ past, Mars Reconnaissance Orbiter with its more global viewpoint has revealed evidence that suggest another possibility: that the apparently periodic “bursts” of water activity might have been the work of large meteoroid impacts blasting through layers of ice and creating temporary episodes of water melt…

To round out the role-call, NASA’s 2001 Mars Odyssey and Europe’s Mars Express orbiters are also still in business and contributing to our already huge–but nowhere near complete–body of knowledge of that wandering orange dot in the sky…

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

latitude: 37.8148, longitude: -122.178