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Image: NASA/JPL-Caltech

The Voyager 1 and Voyager 2 probes — which launched in 1977 and are now traveling through interstellar space — may be complicating scientists' understanding of our solar system's structure.

Why it matters: Mapping the structure of our solar system places it in context with the rest of the galaxy, allowing scientists to learn more about the evolution and even future of our cosmic neighborhood.

Driving the news: A series of studies about Voyager 2 published in Nature Astronomy this week reveals contradicting information about the behavior of particles coming from the Sun and those in the interstellar medium.

  • Before Voyager 1 left the heliosphere — the part of space dominated by the influence of the solar wind — it detected particles from the interstellar medium leaking into the heliosphere.
  • Voyager 2, on the other hand, continued to detect solar particles leaking into interstellar space even after leaving the heliosphere, according to project scientist Ed Stone.
  • Voyager 1 also flew through what's now known as a stagnation region before reaching the heliopause — the boundary where the solar wind is overtaken by the interstellar medium. Voyager 2, however, didn't encounter that region.

Yes, but: Scientists still aren't sure what could account for these differences between Voyager 1 and Voyager 2, which are expected to have enough power to continue beaming back data for about five more years.

  • It's possible the differences could be the result of the Sun's 11-year solar cycle during which the star's activity increases and decreases, Voyager scientists have said.
  • Researchers will also need far more data points before being able to definitively understand the structure of the heliosphere, and there is talk of sending a spacecraft purposefully out to interstellar space to fill in the gaps.

Go deeper

Senate Democrats unveil new income tax for billionaires

Sen. Ron Wyden. Photo: Drew Angerer/Getty Images

Senate Democrats on Wednesday released a billionaires' tax proposal, designed to help support President Biden's social spending and climate change legislation.

Why it matters: Sen. Ron Wyden (D-Ore.), chairman of the Senate Finance Committee, said the Billionaires Income Tax would raise "hundreds of billions of dollars" and would affect approximately 700 taxpayers who have more than $1 billion in assets or incomes of over $100 million a year.

The startup that wants to disrupt big internet providers

Illustration: Maura Losch/Axios

A new startup backed by funding from AOL founder Steve Case and Laurene Powell Jobs wants to break up broadband monopolies across the country.

Why it matters: Internet access has been crucial during the pandemic, but it's not ubiquitous, and it can be both slow and unaffordable in swaths of the country.

4 hours ago - World

Top general: China's hypersonic missile test "very close" to a "Sputnik moment"

Gen. Mark Milley. Photo: Rod Lamkey-Pool/Getty Images

Gen. Mark Milley, the chairman of the Joint Chiefs of Staff, warned Wednesday that China's test of a hypersonic missile is "very concerning" and "very close" to the kind of "Sputnik moment" that triggered the Space Race during the Cold War.

Why it matters: The comments by America's top uniformed general underscore the depths of U.S. concerns about China's rapid military expansion and development of advanced weaponry.