astronomy

Our new results published today in nature communications provide the last piece of a long studied puzzle. We finally found the actual physical mechanism linking between atmospheric ionization and the formation of cloud condensation nuclei. Thus, we now understand the complete physical picture linking solar activity and our galactic environment (which govern the flux of cosmic rays ionizing the atmosphere) to climate here on Earth though changes in the cloud characteristics.

Last month I visited the U of Washington to give a talk in which I discussed the effects of cosmic rays on climate. At the end of it, not one, but two people independently asked me about Overholt et al., which supposedly ruled out the idea that passages through the galactic spiral arms affect the appearance of glaciations on Earth. I told them that the paper had really stupid mistakes and it should be discarded in the waste bin of history, but given that Overholt et al. is still considered at all, I have no choice but to more openly euthanize it.

Since I look for interesting science bits (mostly astro bits) for the Monday coffee of our astrophysics group, I realized that I could share it with the readers including some interpretation (and hopefully some added value) by your humble servant. So, here’s my try. If it works (and won’t be too much time) I’ll continue! Although for the coffee I bring mostly astrophysics and some planetary science, here I’ll also try to bring interesting results in climate (those that aren't lame...).

I was recently asked to write an article to “The Institute Letter” of Institute for Advanced Study at Princeton, where I am spending a wonderful sabbatical year. It briefly describes a very interesting discovery that my colleagues and I made, which is that the 32 million year oscillation of the solar system perpendicular to the galactic plane can clearly be seen in the paleoclimate data. In the article, I also discuss how the discovery came and some of its implications. I am bringing a slightly expanded version here (with more figures and elaborated caption), and references of course. Enjoy.

A very interesting paper recently appeared in nature. It describes the detection of a precursor eruption of a supernova progenitor more than a month before the supernova explosion itself. It is particularly interesting because this detection was not serendipitous—it was based on my prediction.

The CLOUD collaboration from CERN finally had their results published in nature, showing that ionization increases the nucleation rate of condensation nuclei. The results are very beautiful and they demonstrate, yet again, how cosmic rays (which govern the amount of atmospheric ionization) can in principle have an affect on climate.

I recently stumbled upon a nice black hole merger simulation.
Since it is not in my habit of just regurgitating stuff I see on the internet, here is my added value. How can one estimate the quadrupole gravitational radiation of a binary? How close does the binary have to be for it to coalesce within the age of the universe?

A few astro photographs, including one of Saturn under horrible seeing!

From time to time, I hear the statement that Earth's magnetic field is important because it protects earth from "deadly" radiation, and that when the magnetic field will reverse, this lethal radiation will be... very bad. One such example is this promo for a NOVA program called "magnetic storm". Well, I have news. Nothing really bad will happen to us!

After finding out that Earth is not a planet (it didn't clear out its orbit...), I now learned that Earth's doesn't have life on it. Sounds strange? Well, Navarro-González et la., in a recent paper that appeared in PNAS, showed that the same tests used on the Viking program and that came out negative for life on Mars, showed negative results also in ...

After a long embargo, results from the Danish National Space Center (DNSC) Sky experiment were finally published in the Proceedings of the Royal Society. The results demonstrate a clear link between cosmic ray induced atmospheric ionization and the formation of condensation nuclei, thus strengthening the claims that cosmic rays affect cloud cover and climate (and consequently implying that a large fraction of 20th century global warming should be attributed to the increased solar activity).

Last week, a report by Jeff Kanipe appeared in nature. In it, Kanipe explains the solar → cosmic-ray → climate connection, and the planned CLOUD experiment in CERN, expected to finally resolve the issue. Given that my work is mentioned in the review, I through I should mention a few relevant points.