Last week, the MESSENGER spacecraft passed the solar system’s smallest planet for the third and final time; when they next meet it won’t be some quick fling, it’ll be for a long term relationship.
Several gorgeous images were returned from the spacecraft, but this one is my favorite so far:
This is a large impact basin about 260 km (160 miles) across. It’s never been seen before! Only one other spacecraft has visited Mercury before — Mariner 10 in 1974 — and its orbit was such that it never did see many parts of the planet. MESSENGER was in the right place at the right time to snap this picture.
Note that it’s a double ringed crater. It’s not quite clear why these features form. It may be due to the forces generated upon impact, when a shock wave travels through the rock and rebounds inside the crater, or it may be from subsequent volcanic flows. Double rings are only seen in large impact events, so that must have something to do with it. You can also see concentric troughs or cracks in the crater middle. Those are due to the stretching of the crater floor after the impact.
Other images of Mercury from this third pass are just as cool: a bright splash around a double crater (seen here; most likely lighter material under the surface blasted out on impact), a crater with an elongated pit in its floor that makes it a pretty good smiley face, and a lovely shot of the northern limb of the planet spattered with craters.
I imagine they’ll release a handful more images over the next few days, but that’ll be it for the most part until March 2011, when MESSENGER meets up with Mercury one last time, settling into orbit… and then we’ll see lots more images. Lots and lots more… and they’ll be even higher resolution than these. What wonders will we see then?
The spacecraft MESSENGER is just three days away from its third encounter with Mercury. The past two have been nothing short of frakkin’ amazing, so I’m really looking forward to this final pass. Even though it was 1.3 million kilometers away from the tiny planet on the 25th, it snapped this serene shot:
I love moody astronomical pictures. Here, a crescent Mercury sits in the inky black as MESSENGER screams down on it at 3.3 km/sec (2 miles per second). ON this final pass, the spacecraft will slow enough that it will be able to enter orbit around Mercury in March 2011. The nominal lifespan of the mission will be for one solid (Earth) year of observations, and will map the planet with 18 meter resolution. That’s the size of a house.
That is so going to rock. But that’s 1.5 years away, and we’re still waiting on this third pass. I hope to be able to post pix when they come in, but I’m traveling to the UK for TAM London not long after, so we’ll see. But you can always keep an eye on the MESSENGER website, as well as Emily Lakdawalla’s blog. They’ll be up-to-date… especially, if I know her, Emily, who will be spending the flyby looming over her keyboard and hitting "refresh" every 30 seconds or so.
1) The new Carnival of Space is up at Lab Lemming’s tent, and it’s a BIG tent.
2) Emily has news that Phobos is a bit lighter than previously thought. What a pile.
3) Emily also has some nifty new MESSENGER images explained. I’ve been too lazy to deal with that.
4) Tom notes that HiRISE spotted Spirit on Mars. Massively embiggenated version is here.
4) This is dumb. So why did it make me smile so much? Oh right: I’m a dork.
I posted a few days ago that NASA’s MESSENGER probe is headed toward a rendezvus with Mercury on Monday. In the comments, BigBob noted that the first image has been returned!
This was taken on January 11, when the spacecraft was still 1.7 million kilometers from the planet. On Monday, it will pass about 200 km over the surface (yikes!). It will fly on, making two more passes of Mercury over time before settling into orbit, and making a detailed map of this planet. That’ll be in 2011, so the images we see from this first of three flybys will have to do you for now.
