Data analysis of satellite mission on dark energy and theory of gravitation
Researchers, including physicists from Heidelberg University, have gained new insights into dark energy and the theory of gravitation by analysing data from the “Planck” satellite mission of the European Space Agency (ESA).
Their results demonstrate that the standard model of cosmology remains an excellent description of the universe. Yet when the Planck data is combined with other astronomical observations, several deviations emerge. Further studies must determine whether these anomalies are due to measurement uncertainties or undiscovered physical correlations, which would also challenge Einstein’s theory of gravitation. Thus, the analysis of the Planck data gives major impetus for research during future space missions.
From 2009 to 2013, the ESA’s Planck satellite took measurements of the so-called cosmic microwave background (CMB). The CMB is radiation that originated approx. 13 billion years ago, about 380,000 years after the Big Bang.
Due to the expansion of the universe, this light is still observable today at microwave wavelengths across the entire sky. Between 2009 and 2013, Planck surveyed the sky to map this ancient light in unprecedented detail. Now several research articles on the Planck data have been published. The Cosmology research group of the Institute for Theoretical Physics (ITP) at Heidelberg University participated in one of these studies.
“Precise measurements of cosmic microwave radiation reveal minute differences in temperature. On a celestial map, these temperature fluctuations look like small specks. Every speck is a region of somewhat higher or lower temperature,” explains Dr. Valeria Pettorino, junior research group leader at the ITP. Prior findings point to only six parameters that describe the development of the universe after the Big Bang with relative accuracy, using what is known as the standard model of cosmology.
The temperature differences of the cosmic microwave background have allowed researchers to identify these parameters with extreme accuracy. One of them accounts for so-called dark energy, which comprises about 70 per cent of the total energy of the universe and is responsible for its accelerated expansion.
Research into dark energy is still in its infancy. Even though the data from the cosmic microwave background shows that dark energy is required, its composition remains unclear. Using the latest satellite data, the Planck researchers have put various theories to the test that take dark energy into account and are based on modified gravitation – and hence also call into question the theory of gravitation postulated in Albert Einstein’s theory of relativity.
They employed a broad spectrum of methods and other measurement data, including Baryonic Acoustic Oscillations, which are density waves from the early universe, local measurements of the Hubble constant, which specifies the universe’s rate of expansion at the present day, as well as a certain group of supernovae or exploding stars.
From the Planck data the scientists were able to determine just how much dark energy existed in the past. “Surprisingly, the amount of early dark energy was significantly less than we expected. So far, it had been assumed that dark energy comprised a maximum of one per cent of all energy at the time the microwave background radiation was released. But the new Planck results indicate that it could have been no more than 0.4 per cent,” explains Dr. Pettorino. “That’s a big problem for the theoretical models of dark energy which predicted a considerably higher amount of energy for the early universe,” adds Dr. Matteo Martinelli, postdoc at the ITP.
Furthermore, the analysis of the Planck data also revealed small disruptions in gravity itself that are not completely consistent with the standard model of cosmology. Even though these deviations are tiny and vary depending on the dataset studied, they call for further testing and investigation with other sets of data. “Further study might enable us to find out whether we are really dealing with deviations from Einstein’s law of gravity that require a return to the drawing board,” says Valeria Pettorino.
According to the physicist, the analyses are of key importance to cosmological research on dark energy and gravitation. They can give invaluable impetus to upcoming satellite missions, such as the 2020 Euclid mission planned by the ESA and NASA. The astronomical institutes of Heidelberg University will again be major participants in this mission.
Planck 2015 results. XIV. Dark energy and modified gravity.
Dr. Valeria Pettorino
Institute for Theoretical Physics
Phone +49 6221 54-9414
Communications and Marketing
Phone +49 6221 54-2311
Marietta Fuhrmann-Koch | idw - Informationsdienst Wissenschaft
New material for splitting water
19.06.2018 | American Institute of Physics
Carbon nanotube optics provide optical-based quantum cryptography and quantum computing
19.06.2018 | DOE/Los Alamos National Laboratory
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
19.06.2018 | Physics and Astronomy
19.06.2018 | Life Sciences
19.06.2018 | Physics and Astronomy