NASA’s New Horizons deep space probe has sent back images of stellar parallax, the location of stars seen from two different places, to Earth for the first time. This phenomenon could one day be used for interstellar navigation.
Most people have heard of Galileo’s problems with the Catholic Church because he advocates the sun-hearted ness, claiming that the earth orbits the sun. But he had no direct evidence that the earth was really moving. In fact, this is the main reason for Digu Brach’s opposition to Copernicus. If the earth moves, you should be able to see the stars in the sky moving because of parallax.
In 1838, the German astronomer Bethel measured the parallax of a star in constellation 61 and found that the star was 11.4 light-years from Earth. It was only after Galileo’s death that his theory was proved correct.
Today, the New Horizons probe is well beyond Pluto’s orbit, more than 4.3 billion miles (7 billion kilometers) from the sun, and is heading toward interstellar space. On 22 and 23 April, the spacecraft used its long-range telescope to take photographs of Proxima Centauri and Wolf 359, located 4.2 light years and 7.8 light-years away, respectively.
The images were sent back to NASA via radio link, taking about 6 hours and 30 minutes to reach their destination and being compared to images taken on Earth at the same time from the Siding Springs Observatory in Australia and the Mount Lemon Observatory in Arizona. The two sets of images are compared to show a clear parallax.
According to NASA, this is not only the first time the spacecraft has measured stellar parallax, but it is also the longest-ever measurement baseline, as New Horizons is 23 times the distance of the Earth’s orbital baseline. This makes parallax easy to observe with the naked eye rather than precision instruments.
“It’s fair to say that New Horizons is looking at an extraterrestrial sky, unlike what we’ve seen from Earth,” said Alan Stern, lead researcher at New Horizons at the Southwest Research Institute (SwRI) in Boulder, Colorado. “It’s allowed us to do something we’ve never done before — to see the nearest star shift in the sky obviously from where we’ve seen it on Earth. “
NASA says the experiment is not only a record-breaking experiment, it could one day be practical. Currently, deep space probes rely on signals from NASA’s deep space network to navigate, but that would be impractical as the spacecraft moves toward interstellar space. Instead, the on-board navigation system will have to use the new method or adjust the old method. One of them will be stellar parallax, which will allow computers to calculate their position by paying attention to the movement of nearby stars.