Does this dwarf planet have atmosphere?
Not much is known about Makemake, a dwarf planet that circles the sun beyond Pluto. But scientists got a closer glimpse of it last year, when it passed briefly in front of a star , and they report their findings in the current issue of the journal Nature.
Previously, researchers believed that because the surface temperature of Makemake is heterogeneous, it might have an atmosphere.
"If you have some patches with a higher temperature, the ice melts and creates vapour," said an author of the new study, Noemi Pinilla-Alonso, a planetary scientist at the University of Tennessee.
"And with vapour the planet can develop an atmosphere around it." But the new measurements - based on observations from multiple telescopes in different parts of South America - indicate that Makemake, like another dwarf planet, Eris, does not have a significant atmosphere.
The researchers also determined that Makemake reflects about 77 per cent of the sun's light, comparable to the reflection made by dirty snow, and that it is flattened at both poles. Makemake occupies a portion of the solar system with very few stars, so a stellar occultation is rare, Pinilla-Alonso said.
"The fact that we could do this and record it with so many telescopes of different sizes is amazing," she said.
For dogs, word size matters
Toddlers just learning to speak associate words with shape, not size or texture. Anything shaped like a telephone, for instance, might be called 'phone'. But a new study suggests that dogs tend to associate words with size rather than shape.
This difference makes it "very doubtful that there is a single mammalian feature in word learning," said Emile van der Zee, a psychologist at the University of Lincoln in England and the first author of the study, which appears in the journal PLoS One.
"This study may help us understand why humans are more special when it comes to learning language." The researchers worked with Gable, a five-year-old Border collie with an understanding of more than 40 words. The dog was shown a horseshoe-shaped object that the scientists called a "dax." After some training, the dog began to identify other objects of similar size with the same name.
After taking the object home for about a month, Gable also began to associate the word with other objects of similar texture, but never objects that were simply of similar shape.The smells of the objects were kept neutral, but the results may differ if scent is incorporated, van der Zee said. "That would be something that we would like to do in our future research," he said.