In a telephone interview with the site The Scientist from Darmstadt, where the European Space Agency's Science Control Center (the equivalent of JPL) is located, he talks about his successful predictions and our expanding knowledge of Titan
for the enlarged panoramic image
This is a panoramic image that provides a full view - 360 degrees around Huygens. The left part, behind Huygens, shows a border between light and dark areas. The bright streaks seen near this boundary could be ground fog of methane or ethane vapors, as they were not observed in the upper atmosphere. As the spacecraft descended, it drifted over a plain (in the center of the image) and advanced towards the landing site in a dark area (right). This dark area is probably near a drainage channel where there may also be some amount of liquid material. From the movement of the spacecraft, the wind speed was about 6-7 meters per second. The image was taken from a height of about one kilometer with a resolution of about 20 meters per pixel.
Image description - from the European Space Agency website
The interview with Prof. Bar-Nun
Among the dozens of scientists who waited on Friday for the scientific results transmitted by the European spacecraft Huygens, there was also an Israeli representative. Prof. Akiva Bar-Nun, from the Department of Geophysics and Planetary Sciences at Tel Aviv University, is a member of the scientific team of the NASA and ESA (European Space Agency) Cassini-Huygens spacecraft.
The research group of Prof. Bar-Non has been studying Titan's atmosphere for 30 years. She predicted the discovery of propane gas, which was indeed found in the atmosphere by NASA's Voyager spacecraft. Now she predicts the chemical composition of the haze that will be tested when Huygens passes through the atmosphere.
A new experimental result, measured by PhD student Ronen Jacobi, is the capture of the noble gases argon, krypton and xenon in the haze formed in Titan's atmosphere. This capture, together with the deposition of the haze from the atmosphere to the ground of Titan, explains the zero amounts of argon, krypton and xenon in the atmosphere of Titan, as found in the passage of the Cassini-Huygens spacecraft near Titan.
How do you sum up the sale that culminated on Friday?An exception, this is a success for Huygens.
How long have you been working on the project?I have been participating in this project for 15 years and working on Titan for 30 years.
Have you received confirmation of your prophecies?"All my predictions were successful. The first prediction was that there would be no noble gases - argon krypton and xenon in Titan's atmosphere or trace amounts of them, and this is because they are trapped in the haze from aerosols that forms in the atmosphere and descends over time. This haze cleans the atmosphere of these noble gases over time. Another prediction In order for there to be no lightning in Titan's atmosphere, they prepared a special super microphone Huygens detected the thunder and found nothing. There really is no lightning on Titan, contrary to other people's opinions. The microphone was open for the two hours the spacecraft made its way down, which is enough time that if there were thunder we would hear it.
Another point is that we were afraid about 10 years ago that this haze would be sticky. According to our experiments in the laboratory. We were afraid that he would block all the openings of all the devices and interfere with the detectors. Over the years since then we have come to the conclusion that the small grains of haze will harden or harden or harden and therefore they will be like marbles of glass and not like sticky grains. Indeed, the haze grains did not stick to Huygens' detectors.
Were you surprised by the flow signs?"No, although to be careful, as for the very existence of the flow signs, we still need to look at the images and process them much better. Liquids may have to be there because we know that ethane and propane are formed in the atmosphere, and the methane itself can liquefy on the surface of the ground, so we can assume There are liquids there. I assume it's liquid hydrocarbons and there's no reason they didn't form all kinds of streams or wadis, but at least there was no sea or lake in the area of the landing. Because we know the strength of the ground at the landing place.
Is it possible to understand from the photo that there is a sea not far away?This cannot be concluded because even those responsible for the photographs do not say that they saw lakes there. The person responsible for filming did not state this. It is possible that there are lakes there, there is no reason not to, but at the time we thought that maybe the whole area was covered in a sea of liquid hydrocarbons, this landing proved that this is not the case.
What were the surprises?There were not so many surprises, we knew from the last few months and some of the surface of Titan from the photos of Titan. We already knew the composition of the atmosphere from observations from Israel and Voyager in pretty good detail. A pleasant surprise as we had predicted was that they did not find quantities of noble gases there. We know better the temperature and pressure profile in the atmosphere, we know the mechanical strength of the soil in the landing area and we know many other things that we will talk about when we have the opportunity.
A competition between the US and Europe is developing, perhaps a kind of jealousy of writers?The European Space Agency has long been doing projects. One of the most beautiful is Rosetta which was sent last year. There is close and fruitful and very friendly cooperation between the American Space Agency and the European Space Agency and the atmosphere is excellent. I wouldn't call it a competition. This project cost 3 billion dollars, XNUMX billion for Cassini and XNUMX billion for Huygens. There is no reason why these two agencies should not cooperate. Too bad the Russians can't participate.
Is the Israeli Space Agency not in the picture?Israel is not in the picture in this context. Israel is doing other things in space. We had a beautiful project with many partners in SRG - Tavex managed by Hagai Netzer, Noah Barosh and their friends, and unfortunately the Russians stopped developing the satellite to which it was supposed to be launched and it was not sent. Let's hope it will be sent by the Indians.
