Circling Ceres, Imaging Light, and Competing with Oculus Rift | Vol. 2 / No. 19

Around Ceres

Since its discovery in 1801, Ceres has been known as a planet, then as an asteroid, and later as a dwarf planet. Now, after a journey of 3.1 billion miles (4.9 billion kilometers) and 7.5 years, Dawn calls it “home.”

That’s the chief engineer of the Dawn project writing on March 6 about the arrival of the spacecraft in orbit around Dawn that day, over at the Dawn Blog. It’s the first probe we’ve ever orbited around the dwarf planet, even though it’s closer than the gas giants, and maybe that’s because we demoted it from planet to asteroid for so long. But now thanks to the same move that demoted Pluto, it’s finally getting some recognition.

Ceres is the fastest of the five official dwarf planets, making its way around the sun every 4.6 years (for comparison, Eris, the largest, takes 557, Pluto takes 248, Haumea takes 283, and Makemake takes a just under 310 years). This is in large part because the other dwarf planets are at least as far out as Neptune. In fact, Ceres is the only dwarf planet this side of Jupiter, making it unique in the solar system. If you’re not aware, the kerfuffle around the demotion of Pluto was in large part due to the realization that Pluto was one of a huge number of similar bodies out at the edge of the known solar system — it wasn’t even the biggest of those objects (that’d be Eris, at roughly 1.3 times Pluto’s mass). Some scientists estimate that there might be as many as two hundred similar bodies out in the Kuiper Belt, which is what made the reclassification necessary in the first place. At about 950km across, it’s no heavyweight — it’s mass is something between one and two percent of the moon’s. But when it comes to dwarf planets, there’s only one in our neighbourhood, and that’s Ceres.

Now, perhaps its a little premature to be calling it “in orbit” of Ceres. Dawn came via the second-largest object in the asteroid belt, Vesta, so its course is a little strange. Me, I’ll call it “in orbit” when it’s completed its first full orbit, which as you can see by the following youtube video, will be in around two months’ time. But in the meantime it’ll be taking pictures and sending back data, so we’re all pretty happy about that. Check out the video below, and also check out the Dawn Blog and the NASA mission status page for more updates as time goes by.

Snapshot

For the first time, researchers have taken a picture of light acting like both a particle and a wave. By trapping a “standing wave” of light on an extremely tiny wire, and then bouncing a stream of electrons against it, they were able to take a picture of where the electrons and the light wave interacted on the wire. But of course, the interactions couldn’t happen if the light wasn’t also acting like particles (photons), so what we have is a picture of the interactions between wave-particle light and the electrons they were throwing at it. And this is what we get. There’s a great little video here to help you understand the experiment, but if you need help understanding the photo you might need someone a little higher up the pay scale. They can read the article at the journal Nature Communications and relate it back to you.

Competition for Oculus Rift

While it’s still in the “developer kit” phase, Valve has teamed up with HTC to design what looks to be a genuine competitor to the current VR leader, Oculus Rift. More than that, though, unlike OR, it’s definitely designed to be used while walking around. A pair of laser sensors placed in the room with you let it know where the walls are so you don’t walk into them. Oh and it does hand tracking, too. At first I thought VR was going to be another fad, like “3D TVs” or those stupid curved screens, but with two serious competitors in the market (and Microsoft’s slightly-different reality augmentation device) it’s looking like this might really be the way of the future. Now if only we could get something concrete out of Magic Leap. Here’s a review by stuff.tv, and an in-depth analysis and comparison with OR by PC Gamer for more.

Wet Mars

Once again, new research seems to indicate that Mars was wetter for longer than we thought. Maybe long enough to harbour life. In a new study in the journal Science, the researchers measured the ratio of heavier isotopes of water to lighter ones in Mars’s atmosphere and in the polar ice, and used that ratio to infer how much water has been lost over time. The premise is simple: heavier water is lost at a slightly slower rate than regular water, and so as water is lost over time the ratio will change in favour of the heavier isotope. Using measurements from three different telescopes, they came up with ratios of seven and eight times what we see on Earth, which suggested to them that Mars was once covered with an average of 137 metres of water over every part of the planet. If you adjust that for topography, you get a sea that covers something like 20% of the planet. Whether you trust their equations or not (or that Mars started with the same water:deuterium ratio as Earth for that matter), if it’s true that’s a whole lot of a water, and the amount of time life would have had to develop on the planet goes up by a lot. Maybe enough for us to find some fossils. Check out space.com or the Verge for more.

Self-Correcting

One of the big problems with the mechanics of quantum computing — that is, what we’re hoping will one day be quantum computing — is that there’s a lot higher risk of instability for each individual calculation, in which the data could be lost or corrupted. Scientists working at UC Santa Barbara have now created something that could get around that: a nine qubit system that essentially self-corrects by keeping tabs on its neigbouring qubits to ensure the whole system keeps running error free. More importantly, the system works by measuring the data around the calculating qubit, rather than the calculating qubit itself, thereby rendering the calculation still technically unmeasured (remember: if you measure a quantum system, it stops being quantum — thanks Shroedinger). If you need more explanation (god knows I did) check out this article over at phys.org.

Best of the Rest

Like every week, there’s more than I could get to on a Sunday. So here’s a list of things you should totally check out on your own:

• A great article by a former homeopath and woo-practitioner on how she got out and why.
• An interesting opinion piece on how NASA isn’t doing enough.
• An explanation of how scientists are using gravitational lensing to watch the same supernova over and over again.
• News that California may get rid of its “beliefs based” vaccination exemption (hurrah!), and
• News that Google’s new wireless service is only coming to a Nexus 6 near you.

That’s all for today. Have a great week.