The ‘Nano’ in the huge Universe

Speaker:              Prof. Sir Vincent Icke

Department:      Theoretical astrophysics University of Leiden

Location:            TU Delft

Date:                    17-5-2017

Author:                Katja Slangewal

The universe is immensely huge. So, it might be a bit surprising that describing Nano-scale processes are necessary to describe our universe. Until a few years ago the field of Cosmo-chemistry, which focusses on the Nano-scale processes happening in the universe, seemed unnecessary. However, nothing is less true.

The universe exists for 99% of hydrogen and helium. All the other elements we know are filling the final percent. Most of the material is concentrated at stars and solar systems. The rest of the universe is quite empty compared to these dense regions. However, small dust grains, once formed after the dying of a star, are ‘floating’ around in space. The surface of these small dust grains contains attractive and repulsive parts. Which can for instance bind a glycolaldehyde molecule. This event might seem very unlikely to happen considering the density in which the dust grains and glycolaldehyde molecules are found in space. However, one should not forget we are talking about immense timescales. The reaction taking place at the surface of dust grains happen at approximately 50 Kelvin. Also, there is no source of energy anywhere near. So, when a particle binds and the energy excess is released in form of radiation, the changes are small that the particle will leave the dust grain anytime soon. This means that several molecules can spontaneously form at dust grains. This forms the basis for Cosmo-chemistry.

Nearby a star, the conditions are very different from the ‘empty’ universe. A star forms a reserve of energy and a source for water. When stars are just starting to get formed a huge ring of dust will surround the star. The dust is attracted by gravity. Because of the excess of water, the dust grains will be covered in ice. As soon as the star grows and starts irradiating, the ice will melt of for dust grains close enough to the stars. A so called ‘ice line’ is formed. This line determines the difference between the nearby rocky planets that will form and the more far away gas giants. This has happened in our solar system (compare Mercury, Venus, Earth and Mars to Jupiter, Saturn, Neptune and Uranus), but this process is also true for exoplanets. As mentioned before, as soon as molecules bind to the surface of dust grains there will be an excess of energy. This energy is turned into radiation, which can be measured. This has allowed us to image exoplanets and see the difference between the icy ad rocky ones.

The question is, can there be life on the exoplanets. To go deeper into this question prof. Icke told us more about the Miller experiment (figure 1). In this experiment, a primeval soup was made, which has shown to produce complex molecules (like amino acids) within a couple of weeks. The primeval soup contained substances which were present on early earth. The same conditions can be found in black smokers on the bottom of our oceans. Prof. Icke stresses that according to physics life is unbelievably simple. It only contains six elements, some relatively easy molecules and the more complex structures found in a cell are just made of chains from the easy molecules. All the elements needed are synthesized by stars, so no complex processes on a planet are needed. And even from the simple molecules we don’t need much. Take for instance the amino acids. We use only 20, while there are over 500 found in nature. So exo-life is very probable, planets are everywhere and the recipe for life is quite simple.

seminar 11

Figure 1: Millers experiment.

After this very interesting talk on the importance of Nano-processes happening on dust grains, the formation of solar systems and the probability of finding exo-life, prof. Icke continued his talk about Nano-pills, which he calls a spin-off of astrophysics. He thinks DNA specific medication in the future will read of the genetic code and determine which medicine to release in patients. He thinks this will prevent misuse of medicine, since you cannot buy pills and use them for someone else anymore.

To my opinion, the last part of the talk really brought down the rest of the talk. I really liked the main part. It contained a new view on where Nano-processes can be interesting. Also, I think the question of how life originated is very interesting and it gave a fresh look to consider life as something easy and simple. However, I thought it was a real pity how prof. Icke ended his talk. The part about DNA specific medicine was brought as if we had no idea about biology. The talk was given at the Nanobiology symposium, so I think he should have known what kind of study Nanobiology is. He showed us pictures of DNA with an attitude as if we were seeing it for the first time. Also, I am wondering if prof. Icke has any idea about DNA imprinting, translational regulation and other mechanisms which won’t enable a quick DNA readout to decide on medication. This was really a disappointment after such a good start of the talk.


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