Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ESA to look for the missing link in gravity

12.09.2002


Although you can never be certain of predicting future developments in science, there is a good chance of a fundamental breakthrough in physics soon. With a series of unique experiments and missions designed to test our understanding of gravity, the European Space Agency (ESA) hopes to get to the very bottom of it.

Scientists will study space phenomena that do not seem to conform to our perceived understanding of gravity. In this way, they hope to develop a greater comprehension of the Universe.
Gravity is one of the four fundamental forces of nature. It shapes the Universe around us, allowing planets, stars and galaxies to form. However, the more scientists study gravity and its effects on celestial objects, the more mysteries they seem to uncover. One example is the so-called `Pioneer anomaly`, named after the NASA space probes Pioneer 10 and 11, on which the effect was first noticed. The anomaly was revealed when a number of spacecraft were seen to be affected by an unknown force that slowed them down. The same behaviour has now been detected on NASA`s Galileo and the joint ESA-NASA Ulysses spacecraft.


Scientists have known for a long time that there appears to be `too much` gravity in the Universe. They can observe the effects of gravitational forces at work, but the origin of these forces cannot be identified. This `excess` of gravity is usually referred to as `the missing mass problem`, since scientists assume that only matter can create gravity. It is therefore supposed that the Universe is filled with large quantities of `dark matter` that has yet to be detected. What if that assumption is wrong?

Some theories suggest that gravity might pull a little harder at extreme distances than had previously been considered, so the concept of dark matter may not even be necessary. Alternatively, the anomalies may be the result of a fifth force of nature: one that is very weak and only shows up in the remotest regions of space. Space is an ideal testing ground to examine the existing theories. In the apparent weightlessness of space, scientists can detect the most delicate of forces and can measure them with extreme accuracy.

Developing an ambitious series of space experiments and missions, ESA is focusing its efforts on testing Albert Einstein`s Theory of General Relativity, the most advanced description of gravity ever formulated. One of the first objectives is the detection of gravitational waves. General Relativity has predicted their existence but, so far, they remain undetected. These waves should travel through space like ripples on a pond. LISA, a joint ESA-NASA mission, will be the first space mission to attempt to detect such gravitational waves. Finding them would be the ultimate test of General Relativity.

A second objective, to be tested by the ESA Gaia and BepiColombo missions, will be to measure precisely how matter distorts space, searching for any deviation in the amount predicted by General Relativity. Microscope, an ESA mission carried out in coordination with the French National Space Agency (CNES), is designed to test a concept from General Relativity called The Principle of Equivalence. According to this, objects are accelerated by gravity in the same way, independent of their mass and chemical composition. If Microscope detects a violation of this principle, it could be the clearest sign yet of a new dimension to gravity, known as quantum gravity.

Quantum gravity is a much-sought-after theory. Its purpose is to reconcile Einstein`s General Relativity with quantum physics, the most advanced theory describing the fundamental forces in Nature, with the exception of gravity. Quantum gravity supposes that space is granular on the smallest of scales. In a similar way, for example, a beach appears smooth from a distance but is actually composed of individual pieces of sand. Hyper, a mission currently under study at ESA would attempt to detect the quantum granularity of space, as one of its investigations into gravity. Looking further into the future, ESA has taken the first steps in defining a mission which would examine directly the Pioneer anomaly.

With this series of missions, ESA will carry out a unique investigation into the very nature of gravity. This may well provide the next fundamental breakthrough in our understanding of the Universe.

Dr Michael Perryman | alfa
Further information:
http://www.esa.int

More articles from Physics and Astronomy:

nachricht Water without windows: Capturing water vapor inside an electron microscope
13.12.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University

nachricht Columbia engineers create artificial graphene in a nanofabricated semiconductor structure
13.12.2017 | Columbia University School of Engineering and Applied Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

A whole-body approach to understanding chemosensory cells

13.12.2017 | Health and Medicine

Water without windows: Capturing water vapor inside an electron microscope

13.12.2017 | Physics and Astronomy

Cellular Self-Digestion Process Triggers Autoimmune Disease

13.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>