Astronomy
Voyagers 1 & 2 Our Most Distant Travellers
As previously commented on here, the NASA Spacecraft Voyager 1 launched in 1977 to probe giant planets Jupiter & Saturn, journeys ever further away from its place of creation – planet Earth. Currently, as at November 2012, Voyager 1 is approx 11.5 billion miles (18.5 billion Kms) from the earth. Its twin Voyager 2 launched later in 1977 is not far behind at 9.5 billion miles(15 billion km). Both of the probes are nuclear powered and therefore need no other power such as far distant sun’s solar power as used by other satellite probes etc. The nuclear generators should last until the mid-late 2020s. Technology and computer power have evolved since the 1970s, the then cutting-edge computers onboard the Voyagers have about 68 kilobytes of memory. Today a handheld 8-gigabyte iPod Nano holds more than 100,000 times as much data, smartphones and small tablet PCs hold even more data and have far greater computing power than Voyager.
The technology was sufficient and the valiant Voyagers more than fulfilled their mission objectives to capture data and amazing photos on their grand tour of the majestic planets orbiting the outer reaches of our solar system. The probes have been trailblazers, leading the way for more advanced craft to follow and it is hoped eventually human beings.
Sensors aboard Voyager that sniff out cosmic particles are returning intriguing measurements showing the spacecraft is on the cusp of leaving the solar system.
The Voyagers speed of travel is approx 35,000 mph/h (57,600 km/h) 10 miles per second. The Voyagers now weak signal traveling at light speed at 186,00 miles per second (300, ooo0 km per second) takes about 17 hours to reach earth.
Scientists may be seeing the first signs that Voyager 1 is nearing – or may have already crossed – the heliopause, the mysterious boundary between the sun’s sphere of influence and the interstellar void beyond and so begin its journey into the unknown depths of space between the stars.
The sun’s million-mile-per-hour solar wind blows a teardrop-shaped bubble around the solar system, pushing against a stream of galactic particles coming from ancient stellar explosions.
The heliosphere is compressed by the galactic wind in one direction, while it stretches behind the solar system like a comet’s tail.
The heliosphere blocks most dangerous interstellar cosmic radiation from reaching Earth.
Voyager 1 managed some photos of the planets before the cameras were turned off to save precious power. Its sensors now collect and send digital data.
Voyager 2 now doing the same.
In the distant future, should our celestial sojourners happen to encounter other civilisations from other solar systems, onboard each Voyager spacecraft is a golden record, a collection of sights, sounds, and greetings from Earth? There are 117 images and greetings in 54 languages, with a variety of natural and human-made sounds like storms, volcanoes, rocket launches, airplanes, and animals. With the vastness of space, such an encounter would be extremely remote. If not damaged or eroded by interstellar radiation dust and debris, the probes and the golden records could become time capsules lasting many thousands if not millions of years!
Once the Voyagers finally leave interplanetary space to enter into the interstellar domain of the galaxy, it would take the probes approx 50, 000 years to reach the nearest stars to our sun.
One of Voyager I’s last photos taaht of Earth the fragile little blue dot holding us humans -photographed by Voyager 1, nearly 4 billion miles (7 billion kms) from earth
Artististic rendition of the Voyager probes crossing the boundary of the solar system into interstellar space. The sun is at the centre of the blue sphere