This week on Mars:
White bits in this trench vaporized during four martian days (15 - 19 June 2008), proving that they were water ice.
In the lower left corner of the left image, a group of lumps is visible. In the right image, the lumps disappear, similar to the process of evaporation.
"It is with great joy that I report we have found the proof that this material really is water ice," Phoenix principal investigator Peter Smith of the University of Arizona, Tucson, said.
NASA's "follow the water" approach to finding life--or evidence of past life--on Mars has finally hit pay dirt. Three weeks into its 90-day mission, the Phoenix lander has scraped a few centimetres down to an irrefutable layer of water ice in the martian arctic. Phoenix's first digging exposed a thin layer of white material, but team members couldn't tell whether it was ice or perhaps salts. So they waited and watched the trench. In 4 days, at least eight crouton-sized white chunks formed by the digging disappeared, vaporized into the cold, dry air. "Salt does not behave like that," said Smith, "so we are confident now that this is ice."
NASA sent Phoenix to a safe-looking spot where, if past climates were warm enough, that ice might have melted to form a cosy zone for life between the ice and the soil surface. The first robotic contact with water on Mars promises a score of chemical analyses in the next few months that could reveal whether this ice ever melted to liquid water that could have supported living organisms.
The phoenix, of which there is only one in the world, is the size of an eagle. It is gold around the neck, its body is purple, and its tail is blue with some rose-colored feathers. It has a feathered crest on its head. No one has ever seen the Phoenix feeding. In Arabia it is sacred to the sun god. It lives 540 years; when it is old it builds a nest from wild cinnamon and frankincense, fills the nest with scents, and lies down on it until it dies. From the bones and marrow of the dead phoenix there grows a sort of maggot, which grows into a bird the size of a chicken. This bird performs funeral rites for its predecessor, then carries the whole nest to the City of the Sun near Panchaia and places it on an alter there.**
Panchaia is a country or island in Arabia, its name derived from the Egyptian word Pa’-anch, which came to mean an island paradise brimming with spices. Euhemerus of Messene (ca. 300 BC) described a spectacular temple to Zeus Triphilus on Panchaia -- which, needless to say, he had never visited -- built by Zeus himself: it sat on “an exceedingly high hill” and contained a stela of gold inscribed with the deeds of the gods.
A friend of mine once told me that the last practical use of the Classics is for people to give clever names to their pets (two of my three cats, for example). Not so, Prof. John Younger! It's to name places in outer space. For, to come full circle, there is, of course, a spot on Mars called Panchaia, an albedo (radiation reflecting) feature in the northern polar region of Mars -- perhaps not all that far from where the Phoenix lander is industriously digging.
Wouldn't it be fun if that turns out to be the home of the phoenix after all. And well worth telling on a stela of gold.
* From the Fitzwilliam parchment MS 254; dated 1220-1230.
** For more on the phoenix (and other legendary beasties), see the invaluable pages of the Medieval Bestiary.
Update (12 November 2008): Farewell to Phoenix.
As Phoenix nears the end of its prime mission, it has found water ice under the surface, seasonal frost on the surface, water ice clouds in the sky and even falling water ice crystals. Yes, snow falling from ice clouds. You can see it 'snowing' on Mars on the Gizmodo blog.
The Phoenix last conducted science on October 27th, when a perfect storm converged. A combination of ice clouds and a dust storm darkened the sky, causing a dramatic drop in sunlight reaching its solar panels. Power levels reached a critical point. To make matters worse, temperatures dropped to the lowest point of any time in the mission, and the heaters kicked in for the very first time. With that, the last bit of power drained away.
Its systems are built automatically to attempt to jump-start again should the batteries begin to receive power again. On a few days since the storm, when sunlight hit the solar panels, it gave enough energy to send a beep to an orbiter before losing power again.
Its scientific work is done. All its instruments -- including a miniature chemistry lab, an oven to bake samples and analyze their vapors, an optical and an atomic force microscope, a laser (which discovered the snow), and a weather station -- worked valiantly throughout the mission and sent back enough data to keep the scientists busy for months, if not years, to come.
On Monday 10 November, mission control announced they lost contact with Phoenix.
They tell a story of what this bird does, which does not seem to me to be credible: that he comes all the way from Arabia, and brings [its dead] parent bird, all plastered over with myrrh, to the temple of the Sun, and there buries the body. In order to bring him, they say, he first forms a ball of myrrh as big as he finds that he can carry; then he hollows out the ball, and puts his parent inside, after which he covers over the opening with fresh myrrh ...; so he brings it to Egypt, plastered over as I have said, and deposits it in the temple of the Sun. Such is the story they tell of the doings of this bird. [Herodotus Book 2]
Not in a ball of myrrh (as Egyptian priests told Herodotus) but, when temperatures reach -199F (-128C) on Mars this winter, Phoenix will be enveloped in a tomb of carbon dioxide ice. It's hardly credible -- even to us. Farewell Phoenix.
Update (7 July 2008):
As MESSENGER flew past the night side of Mercury in January, its Fast Imaging Plasma Spectrometer (FIPS) scooped up ions from an atmosphere so tenuous that it's usually called an "exosphere." FIPS measured the expected amounts of ions like sodium, potassium, and calcium that had previously been detected in Mercury's exosphere, but to the science team's great surprise, there was also water present, and in large amounts. . "Nobody expected that. I don't know a single person that did. We were astonished, just astonished," said MESSENGER science team member Thomas Zurbuchen.
MESSENGER's journey to Mercury
MESSENGER's trip to Mercury requires a total of six gravity assists (one of Earth, two of Venus, and three of Mercury) to permit it to enter orbit at the small planet close to the Sun. This fabulous animation (above: for the animated version, click on link) shows that journey and the motions of Venus and Mercury using a frame of reference that holds the Earth-Sun line fixed.