Conspiracy theories claim mysterious planet-sized 'Death Star' has been captured on video as it 'refuels' at the surface of the sun

An orbiting Nasa space telescope captured a dark, planet-sized object flying close to the sun on Monday - and extending what looks like a refueling tube into the star's surface.

The black, Death Star-like, orb is briefly engulfed in light from the sun, then flies off into space.

A video edited from the Solar Dynamics Observatory's photos inspired a wave of speculation on YouTube.

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Telescope images of the sun show what appears to be a planet-size dark object extending a 'hose' towards the sun - before it's engulfed by light from the sun, and flies off into space

Youtube user 'Sunsflare' captures the strange orb 'anchored' above the visible surface of the sun in photos from Nasa's Solar Dynamics Observatory

The imagery was captured by Nasa's Solar Dynamics Observatory and edited together by a YouTube user, Sunsflare, who challenged experts to explain the strange 'visitor.'

Naturally, the space agency has a rather more ordinary explanation for the strange, black orb.

It's not a visitor from another solar system - or a planet being born out of the surface of the sun, as others had speculated.

Instead, it's a solar 'prominence' or 'filament' - a feature extending out from the sun which forms over the course of a day, and can extend hundreds of thousands of miles into space.

Scientists are still puzzled as to why these features form. The 'dark' parts are material cooler than the surrounding solar matter.

C. Alex Young, a solar astrophysicist at NASA's Goddard Space Flight Centre said, in a reply to Sunsflare's video, ' Filaments appear to be dark because they're coolerin relation to what's in the background. When you look at it from the edge of the sun, what you see is this spherical object and you're actually looking down the tunnel.'

The video actually shows a solar 'prominence' - a little-understood feature which develops in the surface of the sun. The dark parts are actually cooler material which shows up black against the background

Solar prominences can take a huge number of forms, including huge eruptions like this (pictured), which was captured by Nasa's Solar Dynamics Observatory earlier this year

Nasa says, 'A solar prominence (also known as a filament when viewedagainst the solar disc) is a large, bright feature extending outward from theSun's surface.

'Prominences are anchored to the Sun's surface and extend outwards into the Sun's hot outer atmosphere, calledthe corona.

'Scientists are still researching how and whyprominences are formed.

'An erupting prominence occurs when such a structurebecomes unstable and bursts outward, releasing the plasma.

Nasa's Solar Dynamics Observatory frequently captures the phenomenon - although often as violent eruptions, rather than the eerie sphere of this week's activity.

‘It is not uncommon for prominence material to drain back tothe surface as well as escape during an eruption,’ says Holly Gilbert aGoddard solar physicist.

‘Prominences are large structures, so once the magnetic fieldssupporting the mass are stretched out so that they are more vertical, it allowsan easy path for some of the mass to drain back down.’