Mystery deepens: new study shows comets don’t explain odd dimming of Kepler’s ‘weird star’

The mystery surrounding KIC 8462852 may not involve comets after all, but it is still an enigma for astronomers. Image Credit: NASA/JPL-Caltech
The mystery surrounding KIC 8462852 may not involve comets after all, but it is still an enigma for astronomers. Image Credit: NASA/JPL-Caltech

As has been reported previously, there is something weird going on around a star which is a little over 1,400 light-years away. Astronomers are still baffled as to just what that is, and theories have ranged from a huge mass of comets to alien megastructures. Indeed, comets had become the leading explanation offered for the star’s odd behaviour, although that was really just the best of a bunch of ideas which all had flaws in them. Now, new research shows that the comet explanation is even less likely to be the answer, although the actual explanation is still as elusive as ever. Needless to say, this has resulted in a lot of discussion and debate in the past few months.

Read MoreMystery deepens: new study shows comets don’t explain odd dimming of Kepler’s ‘weird star’

2015 in review: a year of spectacular planetary missions and discoveries

High-resolution view of Pluto from New Horizons, showing rugged mountains and vast icy plains. Image Credit: NASA/JHUAPL/SwRI
High-resolution view of Pluto from New Horizons, showing rugged mountains and vast icy plains. Image Credit: NASA/JHUAPL/SwRI

To say that 2015 has been a great year for planetary exploration would be an understatement, with fantastic new discoveries from around the Solar System. From our first ever close-up look at Pluto and its moons, to more evidence for ancient lakes and rivers on Mars (and current briny streams) to weird bright spots and mountains on Ceres, to the continuing study of Saturn and its moons, notably Enceladus, to spectacular close-up views of a comet, it has indeed been quite a year.

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Rosetta scientists answer question of how ‘rubber duck’ Comet 67P got its shape

Image from July 14, 2015, showing the double-lobed or “rubber duck” shape of Comet 67P and outgassing of water vapor, gas, and dust. Image Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0
Image from July 14, 2015, showing the double-lobed or “rubber duck” shape of Comet 67P and outgassing of water vapour, gas, and dust. Image Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Comet 67P/Churyumov–Gerasimenko, or 67P, has been the focus of intense study by the Rosetta spacecraft since 2014. One of the key mysteries scientists have been trying to figure out is how the comet became the odd “rubber duck” shape that it is, with its two distinct lobes. Now they think they have the answer: Comet 67P was formed by the collision of two other, separate comets which fused together to form its distinctive shape.

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Rosetta spacecraft observes ‘dramatic and rapid’ changes on surface of Comet 67P

Sequence of images showing the surface changes in the Imhotep region. Image Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Sequence of images showing the surface changes in the Imhotep region. Image Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Since August 2014, the Rosetta spacecraft has been orbiting Comet 67P/Churyumov-Gerasimenko, providing an unprecedented look at an active comet as it moves closer to the Sun in its orbit. As expected, the level of activity increased the closer the comet was to the Sun, with jets of water vapour, gas, and dust becoming bigger and more prominent. The comet reached perihelion, the closest point to the Sun on its orbit, on Aug. 13, 2015. For the first time ever, a spacecraft is observing this activity close-up, as it happens. But now, scientists have been noticing other dramatic and rapid changes on the comet’s surface as well, which haven’t been explained yet.

Read MoreRosetta spacecraft observes ‘dramatic and rapid’ changes on surface of Comet 67P