What is Relativity?

Albert Einstein was famous for many things, but his greatest brainchild is the theory of relativity. It forever changed our understanding of space and time.

What is relativity? Succinctly put, it is the notion that the laws of physicsare the same everywhere. We here on Earth obey the same laws of light and gravity as someone in a far off corner of the universe.
The universality of physics means that history is provincial. Different viewers will see the timing and spacing of events differently. What for us is a million years may just be a blink of an eye for someone flying in a high speed rocket or falling into a black hole.

Interesting news:

Indian Regional Navigation Satellite Starts Signal Transmissions

                                                           Germany received signal from IRNSS 1A . I always though that scope of the signal will be more than 1500 Kms outside of india. so whole china is within reach with IRNSS guidance for Nirbhaya, Brahmos and future JDAM like weapons


Indian Regional Navigation Satellite Starts Signal Transmissions | idrw.org

ndian Regional Navigation Satellite Starts Signal Transmissions
Published July 27, 2013 | By admin
SOURCE: Richard B. Langley For GPS WORLD










Scientists from the German Aerospace Center’s Institute of Communications and Navigation in Oberpfaffenhofen, Germany, have received signals from IRNSS-1A, the first satellite in the Indian Regional Navigation Satellite System.

Launched on July 1, 2013, the satellite reached its designated inclined geosynchronous orbit by July 18 with an inclination of 27 degrees and an equator crossing of 55 degrees east longitude. Indian Space Research Organisation (ISRO) chairperson Dr. K. Radhakrishnan announced on July 18 that testing of the satellite’s navigation payload would begin within a week.

On July 23, the German Aerospace Center scientists pointed their 30-meter dish antenna at Weilheim towards the satellite and found that it was already transmitting a signal in the L5 frequency band.



Figure 1 shows the spectrum of the received signal. Centered at 1176.45 MHz, the signal has a single symmetrical main lobe and a number of side lobes characteristic of a spread-spectrum signal. The corresponding IQ constellation diagram is shown in Figure 2. The signal structure appears to be unlike those used by the GPS, GLONASS, Galileo, or BeiDou constellations. Further analysis will be required to sleuth the signal details as ISRO, so far, has not publicly released an IRNSS interface control document (ICD). ICDs characteristically describe a satellite system’s signal structure in detail.




The German scientists caution that “this is a very early snapshot of the current signal transmission and probably both the signal power and the signal quality will change and possibly improve during the in-orbit-testing phase of the satellite’s operation.”