article: Esa’s Rosetta spacecraft has captured stunning images of a dust jet erupting from comet 67P Churyumov-Gerasimenko. The jet may have been caused by a wave of heat reaching ice trapped under the surface, causing an explosion of material. But it is unusual, because so far such activity has only been spotted on the day-side of the comet - not the night, like this. Scroll down for video . This animation shows the jet erupting from comet 67P. The first image was taken at 7:13am BST (2:13am EST) on 12 March, and the second was taken two minutes later. The jet is unusual because it is erupting from the dark underside of the comet, whereas such activity had only been seen on the day side so far. Credit: Esa . The two images, released yesterday, were taken by the Osiris camera on the Rosetta spacecraft from a distance of 47 miles (75km), according to Esa. As the comet gets closer to the sun, its surface gets warmer, causing frozen gases to erupt from the surface, carrying dust particles. But it’s not clear if this caused the jet - or an explosion of material caused by ice sublimating (turning from solid to gas) underground. In the first image, taken at 7:13am BST (2:13am EST) on 12 March, the upper comet can be seen with several rays of dust illuminated by the sun, while the dark underside shows no such features. Two minutes later though, in the second image, a spectacular new jet emerges from the dark side, hurling dust into space at 26ft (eight metres) per second. ‘This was a chance discovery,’ said Osiris principal investigator Dr Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. ‘No one has ever witnessed the wake-up of a dust jet before. It is impossible to plan such an image.’ How or why the activity occurred in the dark region of the comet, though, is not yet understood. ‘It is possible that the first rays of sunlight hit some cliffs or outcrops that remained hidden to Rosetta due to the orbital position at the time,’ said Osiris scientist Dr Jean-Baptiste Vincent, also from the MPS. The Rosetta probe, which carried the Philae lander, launched into space in 2004, using the gravity of Earth and Mars to slingshot its way towards comet 67P/Churyumov-Gerasimenko. It chased comet 67P through space for more than ten years, and entered orbit in August 2014. After a four billion mile (6.5 billion km) journey, the probe then successfully released the Philae lander from its grip to land on the comet on 12 November 2014, travelling at 3.3ft (one metre) per second relative to the comet. But when it first made contact with the surface it failed to fire harpoons that would have kept it attached to the comet. This resulted in it bouncing to a height of 0.62 miles (1km) above the comet before again landing on the surface. It then bounced again, but to a much lower altitude. Philae managed to perform more than 90 per cent of its goals before running out of power. Rosetta, meanwhile, is continuing to orbit and study the comet. From data collected by the two proves, Esa said that water on the comet was different to that on Earth - suggesting water on our world came from an asteroid, not a comet. In the first image (left), the upper comet can be seen with several rays of dust illuminated by the sun, while the dark underside shows no such features. Two minutes later, in the second image (right), a spectacular new jet emerges from the dark side, hurling dust into space at 26ft (eight metres) per second . The Rosetta probe, illustrated, which carried the Philae lander, launched into space in 2004, using the gravity of Earth and Mars to slingshot its way towards comet 67P. It chased comet 67P/Churyumov-Gerasimenko through space for more than ten years, and entered orbit in August 2014 . The region of the comet where this jet erupted from is known as Imhotep. By 7:17am BST (2:17am EST), the region had rotated into sunlight, and the jet was no longer visible against the overexposed coma. This means scientists aren’t sure if the eruption was short-lived, or was a continuous jet. ‘Usually, 67P’s dust-jets are rather long-lived,’ said Dr Vincent. ‘Most of them last for a full dayside rotation of approximately six hours and even reappear in the next rotation.’ Rosetta is continuing to study comet 67P ahead of its closest approach to the sun in August. And engineers on Earth are also hopeful that the Philae lander on the surface will soon get enough solar power to wake up from its slumber. This recent image was taken on 15 April from a distance of 103 miles (165km). It has been processed to spotlight the comet’s activity, including a striking jet on the left, near the neck region . This image was also taken on 15 April, from a distance of 106 miles (170km) from the comet’s centre. It shows the small lobe of the comet on the left, and its large lobe on the right . Rosetta is continuing to study comet 67P ahead of its closest approach to the sun in August. And engineers on Earth are also hopeful that the Philae lander (illustrated) on the surface will soon get enough solar power to wake up from its slumber .
highlights: Scientists in Germany observed a jet erupting from comet 67P .
  The event was captured by the Osiris camera on the Rosetta spacecraft .
  In images two minutes apart, the jet appears on the dark side of the comet .
  It may have formed when melting ice caused an explosion of material .
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