![]() We might even be able to settle whether our solar system, or even just our corner of the solar system, is special. ![]() “Pursuing new avenues like what is proposed here looks very exciting,” Priyamvada Natarajan, a Yale astronomer who specializes in mapping dark matter and wasn’t involved in the University of Zurich study, told The Daily Beast. Zwick’s close survey of our own system could help us answer that question, with possible knock-on effects across the space sciences. It’s also possible dark matter has contours inside a star system. ![]() It’s possible that dark matter is denser inside a star system than it is in the vast distances between systems. For one, we don’t know how evenly it’s spread. But that doesn’t mean we understand it very well. Today, dark matter is integral to astronomy. Shostak later surmised the galaxies had mass we couldn’t directly observe. In the late 1960s, Seth Shostak, an astronomer now most famous for his work on SETI- the search for extraterrestrial intelligence-used a radio telescope array in California to determine that some galaxies were spinning faster than their visible stars indicated they would. The gap got bigger as our instruments got better. The gap between what we can see and what we think is there first became evident in the early 20th century. There’s a lot more gravitational force than we can account for just by adding up the mass of objects in space. Planets and star systems and whole galaxies behave as though they weigh nearly twice as their visible mass seems to imply. Without it, the universe doesn’t make sense. It neither absorbs light nor reflects it. The going theory is that dark matter doesn’t interact with electromagnetic fields the same way visible matter does. In other words, we might not know enough about the matter we can see to start inferring things about the matter we can’t see. In practice, however, it might not be possible to separate the force of dark matter acting on a probe from, say, the force from some unmapped asteroid-or even a loose connector in the probe venting radiation into space. It’s a “unique opportunity” to “improve measurements of the standard gravitational parameters in the solar system,” Lorenz Zwick and his team from the Center for Theoretical Astrophysics and Cosmology at the University of Zurich wrote in a new peer-reviewed study that appeared online on April 22. If we subtract the known forces-the gravitational pull of every nearby planet, moon and asteroid-what’s left should be the effect of dark matter. It involves shooting probes toward the most distant planets in our solar system, Uranus and Neptune, and carefully logging every force tugging on their trajectories. Now a Swiss team has drawn up an intriguing plan-a possible way to get a much more precise read on dark matter. We’ve never directly observed it with any of our instruments, on Earth or zooming through space on some probe. It might make up as much as 85 percent of the mass of the universe, and its gravity affects everything around it. Dark matter is strange, mysterious stuff.
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