A memorable afternoon. Meeting Jayant Narlikar & Halton Arp

Jayant Narlikar talking about microbial life in the stratosphere.

Prof. Jayant Narlikar is visiting the Max Planck Institute for Astrophysics in Garching this week. Today he gave a very interesting seminar on a project he led, for the search of micro-organisms in the stratosphere. You may remember that Jayant Narlikar was a student of Sir Fred Hoyle, one of the most productive and imaginative scientists of last century. Hoyle has done lots of things, and among these is the revival of the panspermia hypothesis, which he put forward together with Chandra Wickramasinghe. In a nutshell, they proposed that microbial life, which they argued is spread all over the places in interstellar space, can ride comets, and therefore life on Earth might have been seeded from space. This of course does not solve the problem of how life started, but it certainly moves the focus away from our good old Earth (and, let me add, gives one final kick to geocentrism). Ideally, in order to test this hypothesis, one would need to take samples of cometary tails and see whether they host microbial life forms (see for instance this paper by Wickramasinghe, Hoyle and Narlikar). Although in the future this might be indeed possible (see for instance the Rosetta mission in route to comet Churyumov-Gerasimenko), we are so far bounded to much closer distances.

A first step in this enterprise is the attempt of detecting life forms high up in Earth’s atmosphere. For this purpose, a group of researchers led by prof. Narlikar, has done two experiments. Very briefly, they have launched two balloons carrying a payload including a series of sterilized and evacuated tubes. Each of them is equipped with a valve that can be opened via a remote control. As far as the height is concerned, one does not want to stay too close to the ground (say the first 25 km or so, which one could say are probably contaminated by microbial forms certainly coming from Earth), neither go too high (above 90 km), because first of all it gets very expensive and then because the air density up there is so low that one would have very little chances to collect any measurable sample. In the end, the combination of these facts led Jayant and collaborators to reach an height of 41 km. I will not go into the details in this post. If you are interested you can find a report on the first mission here. The bottom line is that microbial life forms were indeed brought back by the returning payload (which was of course attached to a parachute). Some of them were found to share only about 24% of the properties of known bacteria (one of them was named as Janibacter Hoylei, in the honor of Fred Hoyle). These bacteria were also found to be much more resistant to UV radiation than any known microbial life form, and this was interpreted as a proof that they had spent enough time in a UV rich environment.

If these bacteria come from the ground, it is not clear how they got so high in the first place. There is no obvious mechanism that would do. On the other hand, if these bacteria come from, say, meteorites, then their presence up there is natural. Jayant mentioned that in the biological community such a possibility is considered with extreme skepticism, because we are used to think that life on Earth started, well… on Earth. To use Jayant’s words: “life coming from the outside would transform a closed system into an open one“. Biologists seem to have hard times in swallowing this. Of course, finding microbial life at 41 km is one thing, proving this comes from outer space is a completely different issue. Let alone the [yet unknown] mechanism that would lift up those life forms, but after all they might just be another form of extremophiles. As you may know, in the ’80 and ’90 several microbial life forms have been discovered in hydrothermal vents and in very deep pits (km under Earth’s surface), living in absence of light, under obstile temperature, pressure, and chemical conditions. This has opened a new chapter in astrobiology, since it has clearly shown that life can take place in conditions which are rather deviant from the ones we used to consider as crucial for life.

Halton Arp (left) and Jayant Narlikar (right) at the Max Planck Institute for Astrophysics (photo by the author).

The final word on the origin of these stratospheric life forms will have to await for an isotopic analysis (similar to the one done for meteorites). If those things are extra-terrestrial, then their isotopic ratios must be different from those we measure for certified terrestrial life forms. The analysis is all but simple… But I am sure it will be attempted in future missions.

I was sitting in the first row of the MPA Seminar Room. To my right I had nobody less than Halton (Chip) Arp. One of the most enthusiastic astronomers I have ever met. And also one of the most unhorthodox ones, for that matter. You know, is one of those astronomers you have read in the text books, and talking to him brings back memories of people like Allan Sandage and Geoffrey Burbidge. Halton has done many things. The atlas of peculiar galaxies just to name one; the sky is full of galaxies that bring his name. Arp 244, Arp 87… he has received many honors and prizes. And he is very famous because of his strong opposition to the Big Bang model. Along this line, he has done quite some work together with Jayant. Actually, just before I took the picture you can see here, he joked  saying that he could do some of the things he did just because he “was sitting on Jayant’s shoulders” (nicely paraphrasing the famous sentence by Newton).

Talking about non-horthodox things. Incidentally, we just got the referee report for our paper on the very old stars, those which would be older than the universe  (see this old post of mine). Guess what? It was brutally rejected by Astronomy & Astrophysics. Admittedly there are some weaknesses, and we will be working on them. No matter what happens to that paper, though, it was worth the attempt.