What do people know about the Sun

Radar bounces off the sun

  • Radar Echoes from the Sun
  • Radar Studies of the Sun at 38 MC/S
    • Jesse C. James, 1966
    • “About 1000 daily radar experiments have been made of the Sun at El Campo, Texas, since April, 1961. This paper presents some of the results of these experiments.”
    • “Briefly, one radar experiment is performed by transmitting a coded signal toward the Sun for 16 min., the round-trip time, and then receiving the echo for the following 16 min. The average transmitted power is 500 kw, and the antenna gain is 33 to 36 db relative to isotropic.”
    • Link to Publication: http://adsabs.harvard.edu/full/1966ApJ…146..356J
    • Direct PDF Download: RADAR STUDIES OF THE SUN AT 38 MC:S 1966

Distance to the sun analysis from radar bounces

The first publication says the radar bounce took approximately 1000 seconds, the second approximately 16 minutes or 960 seconds. Taking the mean we get 980 seconds +- 20 seconds.

When bouncing radar it travels the distance twice, dividing the time in half we get 490 +- 10 seconds for the one-way time to the sun.

The speed of light is 299,792,458 m/s, Radar is part of the non-visible spectrum of light.

The distance is velocity * time.
299,792,458 * 490 = 146,898,304,420 meters
Calculating margin of error:
299,792,458 * 480 = 143,900,379,840 meters
299,792,458 * 500 = 149,896,229,000 meters

That’s between 89,415,551 miles and 93,141,199 miles.


Other measurements of the sun and other planets


With a moderatly priced telescope, people can view the details of the sun themselves: