May 19, 2017 20:51 GMT by dailymail.co.uk

Mysterious 'alien megastructure' star is DIMMING again

Scientists are calling on observatories around the world to point their telescopes toward Tabby’s Star so they can gather new data as it moves through the dimming cycle.

Astronomers have issued an internet-wide ‘call to action’ after discovering this morning that ‘Tabby’s Star’ has once again begun to dim.

The mysterious phenomenon was first detected in 2015, when a star in the constellation Cygnus was found to be ‘winking,’ with dramatic fluctuations in brightness – but, scientists aren’t quite sure what’s causing it.

Among several theories that have arisen, some experts have suggested that a rotating ‘alien megastructure’ known as a Dyson Sphere could be to blame.

Now, scientists are calling on observatories around the world to point their telescopes toward Tabby’s Star so they can gather new data as it moves through the dimming cycle.

In 2015, astronomers spotted a star, known as Tabby's Star that could be seen mysteriously brightening and dimming. Astronomers have issued an internet-wide ‘call for action’ after discovering this morning that ‘Tabby’s Star’ has once again begun to dim  (artist's impression)

In 2015, astronomers spotted a star, known as Tabby's Star that could be seen mysteriously brightening and dimming. Astronomers have issued an internet-wide ‘call for action’ after discovering this morning that ‘Tabby’s Star’ has once again begun to dim  (artist's impression)

TABBY'S STAR 

Tabby's Star, known officially as KIC 8462852, has baffled experts since it was discovered in 2015.

Observations revealed its light dimmed regularly, as do distant stars when their planets pass in front of them. 

But while the stars of most exoplanet systems are seen to dim by a few per cent, KIC 8462852 dimmed by more than 20 per cent over periods of months.

Some have claimed this dimming could be evidence of a Dyson Sphere – a hypothetical structure which could be used by an advanced alien race to harness the energy of a star.

Scientists remain skeptical, offering that the dimming could be explained by a dust ring around the star or a hail of comets passing in between the star and Earth.

‘ALERT: @tsboyajian’s star is dipping. This is not a drill,’ Jason Wright, Penn State Associate Professor of Astronomy and Astrophysics tweeted Friday morning.

‘Astro tweeps on telescopes in the next 48 hours: spectra please!’

And, Tabetha Boyajian – the scientist for whom the star earned its nickname – tweeted ‘CALL TO ACTION!!,’ calling for instruments including NASA’s Kepler to observe the phenomenon.

According to Boyajian, the dip was at 2 percent as of Friday morning, and it ‘looks like it’s the start.’

This will offer scientists an extraordinary chance to measure the light from Tabby’s Star, officially called KIC 8462852, in efforts to uncover the mysterious cause behind the dimming.

Since it was first detected, scientists have been hard at work attempting to explain the fluctuations, which have seen brightness dip as much as 20 percent before reverting to normal.

If an 'alien megastructure' really is to blame, one scientist has suggested that spotting it could be relatively easy – as long as experts focus on the right places.

Scientists are calling on observatories around the world to point their telescopes toward Tabby’s Star so they can gather new data as it moves through the dimming cycle.
Tabetha Boyajian – the scientist for whom the star earned its nickname – tweeted ‘CALL TO ACTION!!,’ calling for instruments including NASA’s Kepler to observe the phenomenon

Scientists are calling on observatories around the world to point their telescopes toward Tabby’s Star so they can gather new data as it moves through the dimming cycle. Tabetha Boyajian – the scientist for whom the star earned its nickname – tweeted ‘CALL TO ACTION!!’

According to Boyajian, the dip was at 2 percent as of Friday morning, and it ‘looks like it’s the start.’ This will offer scientists an extraordinary chance to measure the light from Tabby’s Star, officially called KIC 8462852, in efforts to uncover the mysterious cause behind the dimming

According to Boyajian, the dip was at 2 percent as of Friday morning, and it ‘looks like it’s the start.’ This will offer scientists an extraordinary chance to measure the light from Tabby’s Star, officially called KIC 8462852, in efforts to uncover the mysterious cause behind the dimming

He says that astronomers should turn their attention to 64 pulsar stars near our planet, which he believes offer the best chance of hosting an alien megastructure.  

In a paper published last year, Professor Zaza Osmanov said the alien megastructures are more likely to be shaped like thin discs rather than 'spherical shells.'

If his theory is correct, this would allow a Dyson's Sphere to exist in a star's 'habitable zone.'

And in his new paper, Professor Osmanov argues that if the Dyson's Sphere does exist in a habitable zone, it should be easy to spot using infrared telescopes.

Several theories were suggested for Tabby Star's behaviour, with one expert suggesting that this 'winking' may have been caused by the rotation of an alien megastructrure, called a Dyson's Sphere

Several theories were suggested for Tabby Star's behaviour, with one expert suggesting that this 'winking' may have been caused by the rotation of an alien megastructrure, called a Dyson's Sphere

WHAT IS A DYSON SPHERE? 

A suggested method for harnessing the power of an entire star is known as a Dyson sphere.

First proposed by theoretical physicist Freeman Dyson in 1960, this would be a swarm of satellites that surrounds a star.

They could be an enclosed shell, or spacecraft spread out to gather its energy - known as a Dyson swarm.

If such structures do exist, they would emit huge amounts of noticeable infrared radiation back on Earth.

But as of yet, such a structure has not been detected.

Source: All About Space magazine 

The Dyson Ring, left, is the simplest form of Dyson structure. Creating a Dyson bubble would be an incredible engineering challenge but it is considered to be far more feasible than surrounding a star in a rigid sphere

The Dyson Ring, left, is the simplest form of Dyson structure. Creating a Dyson bubble would be an incredible engineering challenge but it is considered to be far more feasible than surrounding a star in a rigid sphere

Professor Osmanov is urging astronomers to focus their search on 64 pulsar stars.

In his paper, published on arXiv, Professor Osmanov said: 'We have argued that by monitoring the nearby zone of the solar system approximately 64 pulsars are expected to be located inside it.'

But Professor Osmanov has warned that should we find the alien megastructure, it could be extremely powerful.

He said: 'Rapidly rotating pulsars are very powerful and harvesting their energy would be quite profitable, but a habitable zone would be much farther and mass of a material required for constructing the mega-ring would exceed the total mass of all planets, asteroids, comets, centaurs and interplanetary dust in a typical planetary system by several orders of magnitude.'

This suggests that an alien civilisation living on a megastructure could be strong enough to wipe out humanity.

 

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