A planet with three suns
Astronomers have found a planet with more suns than Tatooine – three, to be exact. The planet is a gas giant, like Jupiter, and it takes about 550 Earth years to orbit the largest of the three suns. The other two suns whirl around each other as they, too, circle the largest sun. You can see a video portrayal of the peculiar orbit here. The system is notable partly because the presence of multiple stars within a solar system can destabilize any orbiting planets, making such a system relatively unlikely to be spotted. Scientists aren’t quite sure how the planet came to have three suns, or even what might happen next – chances are the system won’t last long (in astronomical terms).
Global warming is changing how clouds span the Earth
Climate change affects our whole planet, from the ice caps to the tropics. Not even clouds escape unscathed. Now, in a paper published in Nature, scientists have shown definitively that cloud distribution across the Earth has shifted over the last 30 years.
Clouds can have two opposite effects on global temperatures. Dense clouds reflect solar radiation back toward space, but they can also trap thermal heat, which is why cloudy nights are often warmer than clear ones. In addition to affecting temperatures, clouds also respond to changes caused by global warming. The methods we use to track the weather are constantly improving, meaning that the satellites measuring cloud cover and the way we interpret those measurements have changed every few years since the 1980s. For scientists studying long-term changes, this means that the data can be tricky to interpret.
Using several sets of satellite records and a meticulous method for correcting errors in these methods, scientists have now been able to show that clouds are moving toward the poles, and also that they are getting taller on average. They concluded that these changes are both manmade and natural in origin. Part of the reason for the change is the heating of the trophospere – the layer of atmosphere closest to the earth – due to an increase in greenhouse gases. The other reason for the change is due to cooling of the stratosphere – the layer of atmosphere just above the trophosphere – after two volcanoes erupted in 1982 and 1991.
Although predictive models about cloud patterns disagree on many things, the majority agree with these findings. As clouds move away from tropical regions toward the poles, they are less able to reflect radiation away from the earth. Additionally, the taller and thicker the clouds get, the better they are at trapping heat within the earth. Both of these things result in higher overall overall temperatures. The scientists who conducted the study predict that the trend will continue, mainly spurred on by increasing greenhouse gases in our atmosphere.
The three blind mice can see again!
Well, sort of. In a landmark study published in Nature Neuroscience, scientists were able to partially restore vision to a group of blind mice. The mice have a condition similar to glaucoma, which is one of the leading causes of blindness in humans. These mice (and humans with glaucoma) have damage to their retinal ganglion cells (RGCs), which relay visual information to the brain. Unlike many other cell types, such as skin cells or blood cells, RGCs do not typically repair themselves if they are damaged. Any damage to RGCs, as in glaucoma, usually results in permanent vision damage.
RGCs do not normally grow back if they’re damaged, but if there were some way to make them grow back, perhaps there would be a way to restore vision to the blind. In this study, researchers used two methods to try to get RGCs to regrow. One way was to activate something known as the mTOR pathway. The mTOR pathway is a series of genes and proteins that are very important in physical development. As the visual system develops in embryos and very young children, this pathway is very active. In adulthood, the pathway is turned off. The researchers thought that turning this pathway back on might help RGCs be able to regrow, and indeed, this treatment did cause damaged RGCs to grow back to a short extent.
The second method the researchers used was to expose the mice with damaged vision to high-contrast images each day. The reasoning here is that, while the system for relaying messages to the brain is broken, the system for receiving messages from the outside world is still working just fine. These mice, too, experienced some degree of RGC regrowth.
The real success was had by combining the two treatments. Using both mTOR activation and high-contrast images allowed RGCs to grow substantially and reconnect with the brain. Even the greatest success in science is met with challenges, however. Though the mice were able to regrow the damaged cells, they did not perform well on detailed vision tests. In humans, this might translate to a formerly blind glaucoma patient being able to walk around an unfamiliar room without bumping into anything, but it wouldn’t allow them to read or drive. The technology is not ready to be tested on humans, but the team is working in the meantime to get even greater improvements to vision in their mice.
Jess is a fourth year biology PhD student who studies the liver and its regenerative capabilities. In her admittedly limited free time, she enjoys traveling, writing, and being outdoors.