What’s the News: NASA’s considering launching a boat from Earth, hurling it 746 million miles through space, and plopping it onto one of the minus-290 degrees Fahrenheit methane oceans of Titan. This mission to Saturn’s largest moon would the first of its kind to probe an alien ocean and—depending on the weather conditions—could be the first spacecraft to witness extraterrestrial rain. If the proposed mission beats out two other finalists, it could launch within the next five years. “Titan is an endpoint [in] exploring … the limits to life in our solar system,” project leader Ellen Stofan told New Scientist. “We’re going to be looking for patterns in abundances of compounds to look for evidence for more complex or interesting reactions.”
Dinky but incredibly accurate:
the new atomic clock is the size of a matchbox.
What’s the News: The world’s smallest atomic clock has just hit the market, for a cool $1,500. It’s about the size of a cellphone battery, 100 times smaller than earlier clocks, and uses 100 times less power. But don’t reach for your wallet just yet: unless you’re planning to explore a deep-sea trench, snazzy as this new clock is, it won’t give you the time of day.
First came the formulation of an invisibility cloak that could bend light around an object. Then, this spring, German scientists took that idea and made it three-dimensional. Is the invisibility cloak now ready to go 4D? For a study in the Journal of Optics, British researcher Martin McCall’s team adds the dimension of time to the invisibility cloak idea, creating a theoretical “space-time cloak.”
The key feature of the proposed space–time cloak is that its refractive index — the optical property that governs the speed of light within a material — is continually changed, pulling light rays apart in time. When the leading edge of a light wave hits the cloak, the material is manipulated to speed up the light, but when the trailing edge hits, the light is slowed down and delayed. “Between these two parts of the light, there will be a temporal void — a space in which there will be no illuminating light for a brief period of time,” explains McCall. [Nature]
Taking advantage of these differences, he says, it is theoretically possible to imagine a cloak that allows you—at least from my point of view—to transport instantaneously across space.
That’s the minuscule factor by which time speeds up if you’re elevated just one foot higher from the surface of the Earth, according to new study in Science that cleverly demonstrates Einstein‘s general relativity on a human scale. Don’t rush to move into the basement to extend your life, though: That tiny speck of a difference would account for just about a billionth of a second over the span of the year.
Gravity is the key player in this time variance:
Researchers have found fundamental differences between the brains of people who prefer to rise and greet the dawn each day, and those who don’t mind seeing a sunrise, but only if it’s at the end of a long night. A new study used brain scans and alertness tests to probe the brains of early birds and night owls, and found that people tend to favor mornings or nights based at least in part on how they react to a kind of competition in the brain [National Geographic News].
Two factors control our bedtime. The first is hardwired: A master clock in the brain regulates a so-called circadian rhythm, which synchronizes activity patterns to the 24-hour day. Some people’s clocks tell them to go to bed at 9 p.m., others’ at 3 a.m…. The second factor–called sleep pressure–depends not on time of day but simply on how long someone has been awake already [ScienceNOW Daily News]. Sleep pressure builds up as hours of wakefulness increase. The new study, published in Science, suggests that early birds are more susceptible to sleep pressure, giving night owls the advantage in stamina.
Researchers have another clue as to what’s happening in the brains of bleary-eyed air travelers suffering from jet lag: Two groups of brain cells become desynchronized, according to a new study. The study was undertaken in rats exposed to different amounts of light designed to simulate the effects of flying from Paris to New York…. “One group of neurons tells your body it is Paris time and another says that it is New York time. You are internally desynchronized,” [Telegraph], said lead researcher Horacio de la Iglesia.
The body’s circadian rhythm helps us keep track of when it’s time to eat, sleep, wake up and perform other body functions. This system is partly governed by the cycle of day and night. Changing time zones or working the late shift can throw off the body’s sense of timing because it changes the timing of our exposure to light [LiveScience]. The new study, published in Current Biology, examined a tiny section of the brain called the suprachiasmatic nucleus that controls circadian rhythms, and found that while one group of neurons adjusted to a time change relatively quickly, another group that governs dream-filled REM sleep can take up to a week to catch up.
As the year 2008 draws to a close, the world’s timekeepers are giving us a little extra time to wrap up loose ends: They’re giving us one extra second, to be precise. The “leap second” must be added to keep atomic clocks ticking along in time to the planet’s rotation. So at precisely 23:59:60 at Greenwich, England, on New Year’s Eve, there will be a one-second void before the onset of midnight and the start of the New Year…. By the time the transition from 2008 to 2009 arrives in North America the Leap Second will have already been inserted into the world’s timescale [SPACE.com].
The adjustment is necessary because we have two different ways of measuring time. Traditionally, humankind has reckoned time by the spin of the Earth and its orbit around the sun. Under this astronomical arrangement, a second is one-86,400th of our planet’s daily rotation. But because of tidal friction and other natural phenomena, that rotation is slowing down by about two-thousandths of a second a day. Since the 1950s, however, atomic clocks — which are based on the unwavering motions of cesium atoms — have made it possible to measure time far more accurately, to within a billionth of a second a day [The New York Times]. To keep the two measurement systems in alignment, the atomic clocks have to add an extra second about every 500 days.