Voyagers 1 and 2: Where are they now?
These are the most distant objects ever constructed by humans!
In case you missed it, Voyager 1 and 2, both launched in 1977, are still barreling along at about 17 km/second into interstellar space. The initial launch and trajectories placed both Voyagers out of the plane of the solar system, as shown above.
Each instrument is now about 24 and 20 billion miles, 40 and 31 Astronomic Units from respectively from our sun (an Astronomical Unit equals the Earth-sun distance).
After providing enormous information about the outer gas giants (Jupiter, Saturn, Neptune, Uranus), they passed into the solar system’s heliosphere in 2012. At that point, JPL scientists and engineers repurposed each probe mission from the focus on the solar system to investigations of interstellar space. Since then, the probes have been providing data about the complex dynamics of this zone.
The heliosphere is the outermost zone of the solar system. It is where the solar wind slows down and the sun’s magnetic influence wanes. It also shields the solar system from the full effects of the interstellar wind. (Note that while many define the edge of the solar system at the heliosphere, 30-50 AU from the sun, others consider the outer edge of the Oort cloud, 10,00-100,000 AU to be the more appropriate edge of the solar system.) Surprisingly, the electrical activity in this region has been more intense than expected: perhaps a consequence of the solar wind interacting with interstellar radiation.
To extend the life of each mission, about half of the instruments on board each craft were turned off, especially the power draining optical cameras. Unfortunately, the mission of Voyager 1 will be ended soon, as its transmitting system is not working. (At press time engineers at NASA have been able to regain some basic communication with the spacecraft.) Voyager 2 continues to transmit significant astronomical data. Unfortunately, the mission of Voyager 1 will be ended soon, as its transmitting system is not working. Voyager 2 continues to transmit significant astronomical data.
Here’s a link: https://blogs.nasa.gov/sunspot/2023/12/12/engineers-working-to-resolve-issue-with-voyager-1-computer/
Sunspots.
While we are all agog over the fabulous total solar eclipse, we keep getting more mundane yet significant data from two instruments: The Parker Solar Probe (NASA: launched 8/2018) and the Solar Orbiter (ESA & NASA: launched 2/2020). The former is designed to get up close and “touch” the sun. Its specific mission is to study the corona sphere: the turbulent gas ejected millions of kilometers above the sun’s surface. Surprisingly, it is actually much hotter than the surface of the sun at 5600 C.(Some estimates are in the millions of degrees)
On the other hand, the Solar Probe, moving along an eccentric orbit, with distances ranging from 0.26AU to 0.91AU, is designed to survey the outer perimeter of the sun; including its magnetosphere and the transition of the corona sphere to the solar wind.
In the past year, scientists have been able to coordinate the simultaneous activities of both probes to better understand why the corona sphere is hotter than the surface. It was discovered that the turbulence of the nascent solar wind generates heat that warms the corona sphere.
More information is available here:
https://www.cosmos.esa.int/web/solar-orbiter/-/science-nugget-solar-orbiter-and-parker-solar-probe-jointly-take-a-step-forward-in-understanding-coronal-heating
Pluto’s “Hot Flashes”
This dwarf planet is thought to be about 4 billion years old. Recent analysis of data from the New Horizon spacecraft, whose mission ended in 2015, confirmed the presence of a super volcano that erupted a mere few million years ago. What emerged was ice lava that must have come from water deep within Pluto. The presence of a layer of methane ice on the surface of Pluto has, in the past, prevented detection of the water hidden deep below the surface. Scientists also noted the presence of ammonia, hinting at the presence of organic molecules. What the heat source for all this volcanism is, and how the water got there, is gristle for more study. https://arxiv.org/ftp/arxiv/papers/2310/2310.10904.pdf
The Moon and Mars
As you are well aware, enormous scientific and engineering energy is directed towards exploration of the moon and Mars. Rather than review the progress in both domains, which would require a massive volume of Eyepiece articles, here are two links for those who would like to further explore these missions.
Mars https://mars.nasa.gov/mars-exploration/missions/?page=0&per_page=99&order=date+desc&search=
Moon
https://www.nasa.gov/specials/artemis/
The column is produced and edited by Bob Marx. He is a Physics instructor at Hunter College and has been covering astronomy news for the past several years with his program AstroNewsHour.
