Over 4000 exoplanets have been discovered since the first one in 1995, but the vast majority of them orbit their stars with relatively short periods of revolution. But five new planets have been discovered with periods of revolution between 15.6 and 40.4 years, with masses ranging approximately from 3 to 27 times that of Jupiter. A new study using the EULER telescope at the La Silla Observatory in Chile increases the list of 26 planets with a rotation period greater than 15 years.
“The history of life on Earth provides us with a wealth of information about how biology can overcome the challenges of environments we would think of as hostile,” said astronomer Jack O’Malley-James with the Carl Sagan Institute where his interests lie firmly at the intersection between astronomy, biology and geophysics, which is a perfect place from which to explore questions about how life would influence exoplanet atmospheres, climates and detectable biosignatures.
“This is a remarkable time in human history and a huge leap for our understanding of our place in the universe,” said astronomer Keivan Stassun of Vanderbilt University, a member of the TESS science team that will observe 400,000 stars across the whole sky to catch a glimpse of an exoplanet transiting across the face of its star. The stars selected are bright, cool dwarfs, with temperatures roughly between 2,700 and 5,000 degrees Kelvin. The closest are only approximately 6 light-years from Earth.
The future of the AI, artificial-intelligence, algorithm concept for finding planets hidden in data sets looks bright. The algorithm developed by the University of Texas at Austin, in partnership with Google, can be used to probe the entire K2 data set of approximately 300,000 stars. The method is applicable to Kepler’s successor planet-hunting mission, TESS, which launched in April 2018.
Analysis of sites on Mars show that the red planet’s protective field was switched off half a billion years ago, and NASA scientists say they know why. An impact basin deep enough to swallow Mount Everest in Valles Marineris highlight what might be the results of a ancient asteroid collision with the Red Planet switching off its magnetic field, bathing the Red Planet in harmful radiation, and eroding its atmosphere by particles streaming from solar winds.
“The Sun is 10 billion times brighter than an Earthlike planet around it, so that’s a lot of light you have to suppress if you want to see an orbiting planet. A K star might be ‘only’ a billion times brighter than an Earth around it,” said Giada Arney of NASA’s Goddard Space Flight Center. And they live a very long time—17 billion to 70 billion years, compared to 10 billion years for the Sun—giving plenty of time for life to evolve. Also, K stars have less extreme activity in their youth than the universe’s dimmest stars, called M stars or “red dwarfs.”
