Light makes the trip to Alpha Centauri in about 4.3 years. The star system is about 41 trillion kilometers from earth. At 40,000 km / hr it would take 1 billion hours travel time, which is roughly 114,000 years.
About 4 light years.==========================Sorry. "Light year" is an answer to "how far", not "how long".Alpha Centauri is about 4 light years away from our solar system and everything in it,which means that it takes light, radio, and TV from us about 4 years to get there.
A satellite travels at its greatest speed when it is closest to the Earth (perigee) due to the stronger gravitational pull. When a satellite is at its farthest point from Earth (apogee), its speed is slower.
Radio. If you can't talk to them directly by hearing their voices, then it is transmitted by radio.
The moon does not block radio signals sent from Earth, but it can cause disruptions in the signals due to its influence on the Earth's ionosphere. Radio waves can still reach the moon and be reflected back to Earth. NASA and other organizations have successfully sent signals to spacecraft on the moon and beyond.
Radiation other than light and radio waves hardly penetrates Earth's atmosphere.
Actually the nearest star (except for the sun) is Proxima Centauri is next at 4.3 light-years from the Earth. It would take 3.4 years at one light-year/year for radio waves to reach Earth from there. This is because the radio waves are travelling in a vacuum and all electromagnetic wave in a vacuum travel at "C" AKA the speed of light.
Alpha
radio transmission can be heard in hilly areas because of diffraction
alpha
Metal is the material that blocks radio waves and prevents their transmission.
Ground wave propagation refers to the transmission of radio waves along the surface of the Earth. This type of propagation is commonly utilized for medium and long-distance communication, particularly in the AM radio band. Ground wave signals can follow the curvature of the Earth, allowing for extended coverage compared to line-of-sight transmission.
About 4 light years.==========================Sorry. "Light year" is an answer to "how far", not "how long".Alpha Centauri is about 4 light years away from our solar system and everything in it,which means that it takes light, radio, and TV from us about 4 years to get there.
radio waves or radio frequency
I think it's Alpha, isn't it?
By international agreement, nobody on earth legally transmits anything on any wavelength unless he and his equipment are expressly authorized (licensed or otherwise permitted) to do the transmitting, and the transmission is confined to a wavelength (frequency) where that type of transmission and output power are specifically authorized. The frequency band (wavelengths) between 1420 and 1427 MHz (21.000 to 21.112 cm) is legally reserved for radio astronomy and space research.
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Radio waves are in all parts of the atmosphere. Some, but not all, radio waves are reflected from the ionosphere, permitting transmission over greater distances.