The transit light curve gives an astronomer a wealth of information about the transiting planet as well as the star. It is only for transiting exoplanets that astronomers have been able to get direct estimates of the exoplanet mass and radius. With these parameters at hand astronomers are able to set the most fundamental constraints on models which reveal the physical nature of the exoplanet, such as its average density and surface gravity. As mentioned above the transit events do not just give information about the exoplanet, but quite often also information about the star. With telescopes capable of high precision photometry, transit curve anomalies can say something about the activity of the star. An example of this is when an exoplanet crosses star spots (Fig. 2) [source]. This can be seen in the light curve as a small increase in flux due to the light of a cooler part of the star being blocked out.
With a very high precision light curve with a high Signal to Noise (S/N), the light curve can also be used to infer the presence of other planets in the system. Perturbations in the timing of exoplanet transits may be used to infer the presence of satellites or additional planetary companions [source,source].
Credit: Paul Anthony Wilson
When you are typing away at your computer, you don’t know what your fingers are really doing.
That is the conclusion of a study conducted by a team of cognitive psychologists at Vanderbilt and Kobe universities. It found that skilled typists can’t identify the positions of many of the keys on the QWERTY keyboard and that novice typists don’t appear to learn key locations in the first place.
“This demonstrates that we’re capable of doing extremely complicated things without knowing explicitly what we are doing,” said Vanderbilt University graduate student Kristy Snyder, the first author of the study, which was conducted under the supervision of Centennial Professor of Psychology Gordon Logan.
A description of the research will appear in an upcoming issue of the journal Attention, Perception & Psychophysics, which recently posted it online.
The researchers recruited 100 university students and members from the surrounding community to participate in an experiment. The participants completed a short typing test. Then, they were shown a blank QWERTY keyboard and given 80 seconds to write the letters in the correct location. On average, they typed 72 words per minute, moving their fingers to the correct keys six times per second with 94 percent accuracy. By contrast, they could accurately place an average of only 15 letters on a blank keyboard.
The fact that the typists did so poorly at identifying the position of specific keys didn’t come as a surprise. For more than a century, scientists have recognized the existence of automatism: the ability to perform actions without conscious thought or intention. Automatic behaviors of this type are surprisingly common, ranging from tying shoelaces to making coffee to factory assembly-line work to riding a bicycle and driving a car. So scientists had assumed that typing also fell into this category, but had not tested it.
What did come as a surprise, however, was a finding that conflicts with the basic theory of automatic learning, which suggests that it starts out as a conscious process and gradually becomes unconscious with repetition. According to the widely held theory – primarily developed by studying how people learn to play chess – when you perform a new task for the first time, you are conscious of each action and store the details in working memory. Then, as you repeat the task, it becomes increasingly automatic and your awareness of the details gradually fades away. This allows you to think about other things while you are performing the task.
Given the prevalence of this “use it or lose it” explanation, the researchers were surprised when they found evidence that the typists never appear to memorize the key positions, not even when they are first learning to type.
“It appears that not only don’t we know much about what we are doing, but we can’t know it because we don’t consciously learn how to do it in the first place” said Logan.
Evidence for this conclusion came from another experiment included in the study. The researchers recruited 24 typists who were skilled on the QWERTY keyboard and had them learn to type on a Dvorak keyboard, which places keys in different locations. After the participants developed a reasonable proficiency with the alternative keyboard, they were asked to identify the placement of the keys on a blank Dvorak keyboard. On average, they could locate only 17 letters correctly, comparable to participants’ performance with the QWERTY keyboard.
According to the researchers, the lack of explicit knowledge of the keyboard may be due to the fact that computers and keyboards have become so ubiquitous that students learn how to use them in an informal, trial-and-error fashion when they are very young.
Deep and wide view of the Milky Way
This new panorama of the Milky Way by astrophotographer Miguel Claro is really amazing, and you definitely want to click on the image to have access to larger versions! This is an 18-image mosaic taken with a Canon 60Da, with 60 second exposures, and it rivals wide-field images taken by larger ground-based telescopes. The images, were, however, taken from the home of some of the darkest skies and largest telescopes in the world, near Roque de Los Muchahos, in La Palma, Canary Islands. Visible is the hazy band of white light that comes from unresolved stars and other material that lie within the galactic plane, contrasting with interesting shapes within the dark regions of the band, corresponding to areas where light from distant stars is blocked by interstellar dust.
Image credit: Miguel Claro
Luzon Bleeding-Heart (Gallicolumba luzonica)
is a species of ground dove native to the islands of Luzon and Polillo in the Philippines. They get the name bleeding heart due to a unusual splash of blood red feathers on the center of the birds chest making it look like the bird has received a wound and is bleeding out, this illusion is enhanced due to a reddish hue of feathers on the bird’s front which almost look blood soaked. This species behaves in a similar fashion to other ground pigeons in that it eats mostly eats seeds, berries and grubs and is very secretive almost never leaving the forest floor.