Space fans around the world have marked Rosetta's demise with a mix of celebration and poignancy.
"Today is the big moment: #Rosetta lands on #67P and reunites with #Philae *so excited* :D," tweeted one German fan.
Many were sad about the end of the probe, as it headed towards the 4km-wide, duck-shaped comet.
Scientists have used Rosetta to study 67P's characteristics, such as its chemical and mineralogical composition.
Data from the comet has also had implications for scientists studying the origin of the solar system. Perhaps these guys were one discovery?
Many also recalled Philae, the robot lander launched from Rosetta, which dropped onto the comet in 2014.
Philae was lost in February when its battery ran out, but ground control managed to find it again through images Rosetta sent back.
The images and other data suggested Philae landed at an awkward angle and so could only work off one single charge of its solar battery.
More than one person has imagined a happy reunion between Rosetta and Philae.
Rosetta was named after the Rosetta Stone, which was key to deciphering Egyptian hieroglyphs.
Philae is an island in the Nile where archaeologists found another inscription that confirmed their interpretation of the stone.
Those who have been following the mission since it began in 2004 prepared accessories to help them face the end.
And it's not just scientists - the media have also eagerly followed the mission.
And some fans just wanted to mark the moment...
Dr Paul Coxon told the whole story of Rosetta with creative use of emojis:
The NASA Cassini spacecraft tweeted its respects to Rosetta:
As did the Mars Curiosity Rover:
And finally Rosetta's last tweet...
By Tse Yin Lee, UGC and Social News team
Rosetta, the European Space Agency's probe, has crashed on to the surface of comet 67P, ending its two-year tracking mission.