From exoplanet research and Io’s unusual atmosphere to triple supernovas, it’s been an interesting week. Here’s what you may have missed in space and space technology.
Astronomers found a rare triple “superbubble” in a star nursery in M33, our nearest galactic neighbor. Three concentric supernovae form a glowing triple shell around a cluster of young stars. Scientists are examining this large-scale structure and other such odd birds to learn more about how galaxies, and the universe as a whole, evolved.
From Harvard this week comes a compelling and evidence-based answer to the evergreen question: if there’s life beyond our planet, where is it?
The scientists’ logic goes like this: Our sun is an unexceptional G-type main-sequence yellow dwarf. It’s about 4.5 billion years old, more or less typical for a star of its mass. Above three solar masses or so, stars don’t live too long — they expire violently, which the Harvard team thinks means the biggest stars die before complex life could have a chance to evolve. On the other end of the scale, on planets whose atmosphere survived the dangerous early lives of extremely long-lived red dwarf stars, life could take off at its leisure. In such a star system, the probability of life grows by orders of magnitude into the distant future.
In the current generation of stars, we’re probably coming along relatively early in the grand scheme of things. Like the kid with the September birthday, we’re among the first born in our class; the report concludes that in terms of star lifetimes, which is to say in terms of time to emergence of life, we and our Sun are precocious, probably within the first percentile. Those familiar with the Great Filter theory, though, may note that this means that the Great Filter is yet before us.
Arguments that are founded in “but we’re special” logic are difficult to support, but wouldn’t it be something if we turned out to be one of the First Ones? We humans, with all our stories about the Old Ones, the Outsiders, those from Beyond the Rim — wouldn’t it be funny if the Old Ones turned out to be us?
Ceres is the biggest thing in the asteroid belt between Mars and Jupiter. As a dwarf planet with an ice-ball surface covered in frozen ammonia, it’s solidly unattractive for human habitation or even mining. But we’ve got a satellite around it taking spectrographic and gravity readings so we can answer questions about the formation of our own rocky little planet. Recent data from Dawn tells us that Ceres’ interior is made of layers of rock, gravel, and ice, but the boundaries between its layers are messy.
We think Ceres’ internal structure is mostly dictated by its movement, because it doesn’t experience much in the way of tidal forces, and it also doesn’t seem to have changed much since the initial heating event during which the planet’s structure differentiated. Having an outer layer composed mainly of ice supports the theory that emergent properties of Ceres’ own structure are responsible for its strangely crater-less surface.
It’s hard to be superlative about this. Once a day, every day, Io’s sulfur dioxide atmosphere freezes and falls to the surface while Jupiter eclipses the sun. Once the sun strikes the surface again, the SO2 frost sublimates into a gas, and the little moon’s delicate atmosphere bounces right back.
Thanks to recent readings from Juno, too, our portrait of Jupiter and its moons keeps getting better. Io is a frigid, sulfurous moonsicle racked by cryovolcanic eruptions and bombarded by radiation. On second thought, let’s not go to Io. ‘Tis a silly place.
Also, this is actually a preview for next week, but: If you want to watch a meteor shower that won’t disappoint, check out the Perseids. They will peak in intensity over the nights between August 11-12 and 12-13, sometimes approaching rates of 200 meteors per hour — about double their usual count.
Why so intense? As the Earth passes into the orbital path of the Swift-Tuttle comet, its debris form the Perseid shower. But this year, there’s a happy confluence of circumstance. Jupiter’s position in its own orbit means that it’s nudging a greater share of comet debris into our path than we see in most years.
While the Perseids aren’t yet at their peak, they’ve already started, so watch the live webcast from NASA. Better yet, go outside and look up!