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Have citizen scientists found evidence of an alien megastructure?
As with any piece of news like this, I recommend caution and waiting for proper investigation before getting excited. One thing worth noting is that Jason Wright, who is mentioned in the source story and quoted below, hasn't mentioned anything about it on his personal blog..
Citizen scientists, working with data from the Kepler space telescope, may have stumbled on evidence of an alien mega structure - certainly what they've found is evidence of some thing very weird happening around a mature star. The find comes from the Planet Hunters project, where volunteers examine the light patterns from distant stars for evidence of planets orbiting them. One star in particular was flagged by several planet hunters as being strange, and further investigation revealed that it has a swarm of non-planet objects orbiting it. Young stars often have such a collection of debris, but this is a mature star. Led by professional researcher T. S. Boyajian they've published a paper (link here) describing the bizarre light pattern, and showing that most natural explanations are a poor fit.
|Above: Artists impression of a massive comet swarm falling into a star, one possible explanation of the star's strange light.|
To be clear, there are possible natural explanations for this, but they would all involve some sort of special pleading or wild coincidence. One explanation being considered (as an outside chance) is that this could be system of mega structures constructed by an advanced civilisation. Boyajian is now working with Jason Wright ( a professional astronomer who runs the AstroWright blog)and Andrew Siemion, the Director of the SETI Research Center, on a proposal to scan the distant star and it surroundings for radio waves that might indicate technology at work.
“When [Boyajian] showed me the data, I was fascinated by how crazy it looked,” Wright told theatlantic.com. “Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilisation to build.”
|Above: Artists impression of a Dyson Swarm, a theoretical megastructure that would absorb all a star's light for energy.|
I don't know if this will turnout to be natural, artificial, a mistake, or even a hoax, but I'll keep my eye on it.
Rivers on Mars once grew to dozens of kilometres in length
Evidence from the shape of pebbles in ancient stream beds, examined by the Curiosity Mars rover, suggests that they were moved for dozens of kilometres by the streams they were in. That suggests that rather than the tiny trickles that the Martian surface sees today, rivers on ancient Mars may have been extensive and long lasting. The team began with mathematical models of how transport changed a pebbles shape, and then compared these to lab tests and real world examples:
"Knowing whether pebbles in a river moved 1 kilometre or 100 kilometres could tell us how stable water was on the surface of ancient Mars. We started at the headwaters [of a mountain river], where chunks of angular rock are breaking off from the walls of the stream, and went downstream," Douglas Jerolmack, one of the co-author's said. "Every few hundred meters, we would pull thousands of rocks out and take images of their silhouette and record their weight."
|Above: An impression of an ancient Martian river by freak-angel56 on deviantart.com|
Hydrogen gas May have warmed ancient Mars
Hydrogen, released from either volcano's or a series of asteroid impacts, may have been what warmed ancient Mars enough to produce the long lived lakes and streams now though to have existed there billions of years ago. Data gathered by NASA's Curiosity Rover, launched in 2011 and currently on Mars, suggests prolonged, standing liquid water was present in Gale Crater. James Kasting, Evan Pugh Professor of Geosciences, led a team using photochemical models to simulate different aspects of the atmosphere . Natasha Batalha, graduate student in astronomy and astrophysics, Penn State who worked on the project said:
"While Curiosity [Mars Rover] couldn't directly prove our hypothesis about a high hydrogen atmosphere, if you get millions of years of warmth, then you're driven towards hydrogen because we haven't been able to figure out any other way to create that warmth. All of the other greenhouse mechanisms fail in our models."
|Above: Artists impression of a warmer ancient Mars, where active volcano's are breaking through the ice of an arctic ocean.|
Cassini spacecraft will take a close look at ocean bearing moon Enceladus today
Enceladus, a moon of Saturn that's barely bigger than the British Isles, surprised us all when it turned out to have an ocean, warmed by a still mysterious heat source, beneath its ice covered surface. NASA's Cassini mission, which has been exploring the rings and moons of Saturn for many years now, has flown past Enceladus repeatedly, and found that the moon has geysers of water jetting from its south pole, apparently carrying water from the ocean into space. However Cassini has never been able to get a good look at the north pole, because Enceladean seasons have kept it shrouded in wintry darkness. However the seasons are changing, and today (Wednesday the 14th October) Cassini will fly to within 2000 kilometres of the polar surface, looking for geological clues to what keeps this tiny moon so warm and active.
|Above: The 'tiger stripes' on Enceladus, where water from the ocean is pushing through the icy surface. Courtesy of JPL/NASA|
Jupiter's Great Red Spot is still shrinking, but the rate has slowed
The Hubble space telescope has seen some odd changes in the weather patterns of Jupiter, as part of it's OPAL program to return more detailed maps of the giant planet. Ever since the 1930's it's been known that the Great Red spot, a titanic storm that could swallow the earth whole, has been slowly shrinking. Hubble has found that the storms shrinkage isn't as fast as it used to be, raising hopes that the mysterious feature might one day stabilise. At the same time Hubble has found a strange 'wisp' or filiment, of cloud crossing the spot, and a rare wave structure just north of Jupiter’s equator that’s only been seen once before. It resembles a it resembles atmospheric features on Earth called baroclinic waves, a large-scale meandering of the jet stream.
|Above: The strange waves, as caught by Hubble. Courtesy of NASA/ESA|
Above: A very cool animation of the OPAL map of Jupiter, wrapped into planet-shape. Courtesy of NASA/ESA