According to new results published by Dr. Henrik Svensmark of the Danish National Space Center in the journal Astronomische Nachrichten, the variability in the productivity of life is closely linked to the cosmic rays, the atomic bullets that rain down on the Earth from exploded stars. They were most intense during a baby boom of stars, many of which blew up.
‘The odds are 10,000 to 1 against this unexpected link between cosmic rays and the variable state of the biosphere being just a coincidence, and it offers a new perspective on the connection between the evolution of the Milky Way and the entire history of life over the last 4 billion years,’ Dr Svensmark comments.
Dr Svensmark looked at the long record of life’s bounty given by counts of heavy carbon atoms, carbon-13, in sedimentary rocks. When bacteria and algae in the ocean grow by taking in carbon dioxide, they prefer the ordinary carbon-12 atoms. As a result, the sea becomes enriched in carbon-13, which is acceptable to sea creatures building their carbonate shells. Variations in carbon-13 therefore record how much photosynthetic growth was in progress when the shell-makers were alive – in other words, how productive the biosphere was at that time.
To his surprise, Dr Svensmark noticed that the biggest fluctuations in productivity coincided with high star formation rates and cool periods in Earth’s climate. Conversely, during a billion years when star formation was slow, cosmic rays were less intense and Earth’s climate was warmer, the biosphere was almost unchanging in its productivity.
This reveals a link more subtle than any straightforward idea of, say, a warm climate being life-friendly or a cold climate deadly. The record shows that in all icy epochs the biosphere kept lurching between exceptionally low and exceptionally high productivity. The suggested reason is that, although ice is unfriendly to life, winds are stronger when the world is cold. By stirring the oceans, they improve the supply of nutrients in the surface waters so much that productivity can be higher than in a warm climate. And this, in effect, enlarges the fluctuations in biological productivity.
Most likely, the variations in cosmic radiation affected biological productivity through their influence on cloud formation. Hence, the stellar baby boom 2.4 billion years ago, which resulted in an extraordinarily large number of supernova explosions, had a chilling effect on Earth probably by increasing the cloud cover.
This is one of a number of new perspectives on climate change arising from the discovery that cosmic rays promote the formation of clouds, which have a cooling effect on the surface temperature of Earth. Recent experiments on how the cosmic rays influence cloud formation were reported in DNSC press release 3 October 2006.
Sune Nordentoft Lauritsen | alfa
Major discovery in controlling quantum states of single atoms
20.02.2018 | Institute for Basic Science
Observing and controlling ultrafast processes with attosecond resolution
20.02.2018 | Technische Universität München
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
20.02.2018 | Life Sciences
20.02.2018 | Medical Engineering
20.02.2018 | Physics and Astronomy