In an earlier post, Close Encounters , I mentioned three memorable astronomical events in 2015. One of them was the flyby by the New Horizons spacecraft of the (dwarf) planet Pluto on 14 July at 11:49:58 UTC (7:49:58 pm Malaysian time)
One day earlier, when the New Horizons was still a respectable 800.000 km away from Pluto, it took this picture.The heart-shaped region, the smooth surface, caused already much excitement
New Horizons was approaching Pluto at a speed of ~ 50.000 km/h, so the flyby was near. At this high speed the observation window for taking close-up pictures was narrow. It was decided to stop communicating with the spacecraft during the flyby, as the on-board computers would be busy collecting data. There was a lot of tension in the control room during the blackout. Here is the response when the first signal of New Horizons after the flyby is received. Mind you, it takes about 4.5 hours for light and radio signals to cross over form the spacecraft to Earth, as the distance to Pluto is about 5 billion km at the moment.
This first signal was only a sanity signal that everything was working normally. Transmission of the images is a time-consuming process. It was only the next day that NASA published the first detailed image.
Many surprises. The surface looks very smooth, scientists think it can not be more than a few hundred million year old. Has Pluto still an active interior? And there are mountains, up to 3 km high. They might consist of water ice.
A second picture has been published today, details of Pluto’s (principal) moon, Charon.
More excitement. Impact craters here, but what is this strange feature in the top left corner? More pictures will arrive and hopefully be published in the coming days. But the analysis will take months if not years.
New Horizons has done a marvelous job. It will now pass through the Kuiper Belt and leave our solar system. You can follow the spacecraft on the New Horizons website
What about the two other events?
Dawn has successfully entered orbit around Ceres and is still observing the asteroid. The white dots on its surface have not yet been explained. Here is a collage of images taken by Dawn. The Dawn Blog is still online and active
Finally Rosetta and Philae
Rosetta is still orbiting comet 67P, which is now on its way to perihelion, the closest distance to the Sun. Perihelion will be reached on 13 August. Already the comet is feeling the heat of the Sun and partly evaporating. This picture was taken on 7 July
Mixed news about Philae. There was huge excitement when it came out of hibernation on 13 June and “talked” for a few minutes with Rosetta. But after that, communication has been intermittent, for reasons unknown. However, ten days ago, Philae has contacted Rosetta again and actually transferred data from one of its on-board experiments! The scientists are hopeful that it will get more active the next few weeks. Read more on the Rosetta/Philae blog
I will update this post when more news/pictures become available
Yesterday NASA published another picture, a detail of the heart-shaped area , which has been provisionally named Sputnik Plain. Some features have been identified. This icy plain can not be more than 100 million old. More details here