Probes Voyager

In 1977, the space probes Voyager 1 and Voyager 2 were sent in the solar system bound for distant planets (Jupiter, Saturn, Uranus and Neptune). The images that come to us again in 2011, often reflected in our past but also show us our future.
"If there was a Nobel Prize for space probes, it would undoubtedly at Voyager 1 and Voyager 2 that have revolutionized our understanding of planets and continue to make discoveries almost thirty-five years after their launch." Rosine Lallement, an astronomer at the Paris Observatory. At year end 2011, Voyager 1 is 17.9 billion miles and Voyager 2 to 14.5 billion km.
They have long since passed the gas giants.
Voyager 1, the fastest, travels at a speed of 17 km/s (about 60 000 km/h), it is about to leave the solar system crossing the boundary, the heliopause. The heliopause is the theoretical boundary where the Sun's solar wind is stopped by the interstellar medium. Once freed from the gravitational forces of the solar system, the probes will start in the infinite space of the Galaxy, new random stellar influences.

The distance of the probes does not allow astronomers to get information in real time, because the distance makes the operation more complicated and asynchronous. A radio signal takes almost 17 hours, at the speed of light to reach Voyager 1. NASA estimates that the energy supplied by three radioisotope thermoelectric generators should operate until 2020. In 2020 its distance has grown from 4.8 billion km, it will be about 22 billion km.

Image: This image of 2011 positioning, Voyager 1, launched in 1977, it is 17.9 billion km. Its signal is 17 hours to go 117 times the Earth-Sun distance. Pioneer 10 was 15.4 billion km from the Sun, Voyager 2 to 14.5 billion km Pioneer 11 and 12.4 billion km, well beyond the orbit of Pluto. Below the Pluto probe New Horizons is 3 billion km. All these spacecraft sent by man, used the effects of gravitational slingshot for speed. Voyager 1 is the fastest with a speed of 17 km/s.

Voyager 1 is the first space probe that sent us detailed images of the moons of Jupiter and Saturn.
In 2011, 34 years after its launch, it continues to send scientific data.
These 825 kg of metal, full of 20th century technology, takes forever, deep in the Galaxy, its scientific instruments (camera, sensor, particle detector).
These instruments, for the study of our solar system will travel forever, to other stars without warning.
If Voyager 1 and Voyager 2 is heading to Proxima Centauri, the nearest star, they would reach the next star system, in about 75 000 years.
These traces of humanity waiting to testify to the existence of extraterrestrial life, that of a beautiful blue point, become very small in deep space between the stars.
On February 14, 1990, NASA control probe Voyager 1, turn around and photograph the planets it had exceeded (pictured against).
Of the 60 images of this unique event, one of the images that Voyager was sent to the Earth 6.4 billion kilometers, 42 times the Earth-Sun distance.
And yes it is us, the little pale blue dot, lost in the immensity of the Universe, which receives the dim light of the sun yet visible.

The solar wind travel at maximum speed to about 95 AU, three times the distance from the last planet (Neptune) in the solar system.
The heliopause is the last frontier of the solar system is the limit where the solar wind fades and where interstellar space begins. At this point the solar wind collides with the opposing winds from the interstellar medium, its thrust is no longer sufficient to push the gas of the Galaxy, the rarefied hydrogen and helium.
The termination shock is a boundary through separated from the heliosheath by the heliopause, the turbulence where the solar wind is slowed and compressed by the interstellar pressure.
When particles from the sun collide with interstellar particles, they slow down, heat up and emit energy. These particles accumulate at the heliopause, highly energized, creating a shock wave. This shock wave is the trace left by the Sun during its journey through the Milky Way.
The distance to the heliopause is not precisely known because it probably varies depending on the solar wind speed and the temporal density of the interstellar medium. In this region called the "magnetic highway", the instruments have recorded the highest rate of cosmic rays from outer space and a sharp decrease of particles from the Sun.