The stars in the night sky have fascinated humans for as long as we have existed. The two connected disciplines of astronomy and astrology have attempted to impose meaning and structure on their patterns and movements for almost as long. However, it is only in the past fifty or so years, with the advent of strong radio-telescopes and mass spectrometry techniques, that we have been able to cast a scientific eye on these dizzyingly huge nuclear reactors that exist untold billions of miles away. But which then, are some of the craziest and most mind-boggling stars with unusual properties that we know of?
You may have heard of this one, it hit headlines around the world back in 2015. Why? Well KIC 8462852, as this star is more properly designated, was observed to be randomly dimming its brightness – by up to 20% at a time.
This might not seem like much. But when we are talking about the huge scales we’re dealing with here – Tabby’s Star is 1.5 times bigger than the Sun and lies 1470 light years or 8.64 quadrillion miles away – then you can see why such a dramatic shift is interesting. For a Jupiter sized planet orbiting a star that size, you would expect a maximum dip of one or two percent at most.
What’s more, a planet would create a regular pattern of decreasing light as it travels on its orbit around the star. Not so for Tabby’s Star. The Kepler Space Telescope observed its magnitude fluctuating different levels at different times over a period of two years. In 2018 scientists have now appeared to have ruled out an alien megastructure as the cause, but the real reason is still unknown.
A bit close to Earth this one, at a cool 190 light years (just 1.1 quadrillion miles, give or take a few trillion), Methuselah is the oldest star known to humankind. Officially known as HD 140283, it was named after the longest-lived character in the Bible. It has been known to astronomers for hundreds of years, as it easily visible by small telescope and is actually one of the fastest travelling stars in our ‘local’ neighbourhood.
Originally, scientists calculated this star’s age as being a fair few years older than the observable universe – at 16 billion years. This, obviously, created a bit of a quandary. Which was only solved in 2013 when the Kepler Space Telescope used new techniques to define its luminosity and metal content to derive a more accurate age of 13 billion years. Which puts Methuselah’s birth as shortly after the big bang.
One of the brightest stars in the night sky, and easily visible to the naked eye, Vega is therefore one of our most studied stars in the Milky Way. What makes it objectively unique though, is the relatively fast speed of 275 km/h at which it constantly spins. This gives it a visibly elongated egg shape, as opposed to the perfect sphere you would normally expect from a star. Maybe the aliens responsible for Tabby’s Star might crack it open for their next breakfast?