Small non-open satellites may be hiding near Uranus and, probably, in other places.
In the 1970s and 1980s, twin spacecraft Voyager 1 and Voyager 2 were sent to NASA with a mission to explore the Solar System. Both probes were studied near Jupiter and Saturn, and Voyager 2 continued its movement towards Uranus and Neptune.
The spacecraft was able to make many discoveries, including the discovery of several satellites in each system. But many years later, after Voyager 2 left Uranus in 1989, using a small number of spacecraft to study the outer part of the solar system, we continue to find new satellites. To everyone's surprise, some of them were discovered with the help of new technologies within the old data received from Voyager.
Other findings were provided by the venerable Hubble Space Telescope, which has been navigating the Earth’s orbit since April 1990. This means that even decades after the Voyager mission, there are probably new satellites waiting to be discovered. Moreover, this probability is enhanced due to the presence of the keen eye of the James Webb space telescope, which plans to start its work in 2018.
Part of the curtain can lift the Cassini factor. Scientists have received a lot of new information about the behavior of rings, and about the influence of satellites on them, as the mission has been studying Saturn since 2004. Recently, researchers applied this understanding to the Uranus system, using data from Voyager obtained in 1986. They found regular patterns in the rings, which show that there may be satellites. “There were very clear periodic changes in the structure of alpha and beta rings,” said Matthew Hedman, a research physicist at the University of Idaho, and a former participant in the experiment led by doctoral student Rob Chancia. - “The clouding of the ring periodically changed after a couple of kilometers. Strange in the structure was that in different places it had different wavelengths. And this did not happen over the entire length of the ring, and there are many ring structures. ”
The closest analogue that can be offered would be something that looks like a “moon rake”. Although this term sounds a bit strange, in fact it describes the process when the moon “clings” to the material on the other side of the annular division. For the first time this phenomenon was described for the Enke Division - a known gap in the outer rings of Saturn.
But here the story stops, at least for now. Hedman and his graduate students are going to soon publish their results in the Astronomical Journal (Astronomical Journal) in the hope that someone more competent in studying data from spacecraft will be able to find possible satellites. Hedman will continue to study and compare ring structures throughout the solar system, since not all oddities can be attributed to the likely presence of the moon.
There is a researcher who can rightfully carry a torch of a veteran in a hunt for satellites. Mark Scoulter of the SETI Project Institute was the first to describe the moon rakes. He processed images from spacecraft such as the Voyager. He was a graduate student when the spacecraft passed Saturn, and continued his work after defending his doctoral dissertation during the approach to Uranus and Neptune. The thirtieth anniversary of the hunt for satellites came just in 2013, when his team with the help of the Hubble telescope announced the discovery of another moon around Neptune. So how did Voyager manage to get right near the moon and not notice it? Schoulter said that the camera was built on technology from the 1970s, and it works in low light conditions. He also discovered the moons of Uranus (Cupid and Mab) in 2003. In the Voyager data, one of them was almost invisible, and the second was barely detectable.
In his next project, he is again going to monitor Uranus to see if there are still possible satellites there. “I have a lot of data about Uranus from Hubble,” he said in an interview. “Now that I know where to look (based on the results of Rob and Matthew), I plan to explore the Hubble data archive about Uranus to find at least a small chance of having these small objects.”
Besides the fact that these incredible discoveries excite the public, there are more fundamental things that these new satellites can teach us. Regarding Neptune, Shoulder was fascinated that his tiny lunar discovery in 2013 did not follow the pattern from the smallest to the largest moons (from the center of Neptune to the outside) previously found in the system. He noted that the planet's system was completely changed by capturing Triton (a very large moon) in the early history of the solar system. But it is very difficult to understand all the dynamics with the information that we possess.
Some lunar secrets lie in other parts of the solar system. When the New Horizon spacecraft approached Pluto, it was able to detect the Styx and Kerber along the way in 2011 and 2012. Satellite Nikta was also found in 2005, a year before the launch of the vehicle. (All three finds were part of the “Pluto Search Campaign”, which were given special missions for the flight of the New Horizons). Previously, only the satellite Charon, discovered in 1978, was known. “The Pluto research team was intrigued that such a small (dwarf) planet could have such a complex array of satellites,” said NASA representatives in 2012. “This discovery provides new clues to understanding how Pluto’s system was shaped and developed. A favorite theory insists that all satellites are relics from the collision of Pluto and other large objects from the Kuiper Belt billions of years ago. ”
And earlier this year, the moon was found in orbit the dwarf planet Makemake, reinforcing the idea that all dwarf planets have satellites. For its search, the same methods were used that were used to detect Pluto satellites in 2005, 2011 and 2012. Other searches on Makemaka did not find anything.
“Our preliminary estimates indicate that the lunar orbit seems to be an edge. This means that when you look at the system, you can skip the moon, as it is lost in the bright light of Makemak, ”said thermal imager Alex Parker from the Southwestern Research Institute in Colorado in a statement at the time. (By the time this article was published, Parker did not respond to requests for an interview).
