Chaotic era (6/8/23)

Good afternoon, and happy Thursday. Hope you’re staying safe and breathing easy out there.

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Colors of the Wind

Five years ago, NASA hurled a little spacecraft towards the Sun. That craft has braved the vastness of space and used Venus’ gravity to angle itself into the uncharted territory of the Sun’s solar corona, where it’s collecting the first ever in-situ observations of the dynamic solar surface.

Now, the Parker Solar Probe has begun to uncover a long-held mystery: the origin of the solar wind.

In a study published yesterday in Nature, a team led by researchers at UC Berkeley and the University of Maryland-College Park were able to use Parker Solar Probe observations to nail down the precise structure of the solar wind at its origin, and found that the Sun expels charged particles most quickly at roughly evenly-spaced locations where the magnetic field funnels into and out of the surface.

The solar wind: The Sun is constantly emitting charged particles that stream through space and collide with Earth at incredible speeds, often at more than a million miles per hour. This outpouring of plasma is called the “solar wind,” and it has a tendency to wreak havoc on orbiting satellites and energy systems on Earth when it acts up.

Predicting fluctuations in the solar wind is no easy task. We tend to have very little warning when a geomagnetic storm is about to strike, and though we have some understanding of the Sun’s 11-year cycle—right now, the Sun’s in its chaotic era—we’re not able to forecast with much accuracy the precise timing or strength of boosts to the solar wind.

Understanding its source, researchers hope, will help us to solve that problem.

Where it all began: The solar wind becomes more muddied and mixed the farther it gets from the Sun, and the structures it may have contained at its source become increasingly difficult to parse. To gain information about those structures, the Parker Solar Probe had to get close (cosmically speaking). It inched up to within 13 million miles, or ~25 solar radii, of the surface.

At that altitude, researchers could tell that the probe was passing through individual jets of material rather than a consistent outpouring from the surface. These jets were spaced fairly uniformly apart, leading researchers to believe that a consistent process was leading to their formation.

The solar wind “doesn't just come from everywhere in a coronal hole, it's substructured within coronal holes to these supergranulation cells,” Stuart Bale, lead author on the paper, said in a release. “It comes from these little bundles of magnetic energy that are associated with the convection flows. Our results, we think, are strong evidence that it's reconnection that's doing that.”

• Reconnection = the result when two oppositely directed magnetic fields pass by one another as they funnel in and out of the Sun, causing them to break and come back together.

• The probe identified particles traveling 10 to 100 times faster than the average solar wind speed close to the surface, which researchers believe could only occur through magnetic reconnection.

Coming up next: The Parker Solar Probe still has a long mission ahead of it, and researchers plan for it to get a lot closer to the Sun’s roiling surface before its time is up. So far, the probe has completed five of seven Venus flybys, each of which has brought it closer to the solar surface. After its last two flybys in Aug. 2023 and Nov. 2024, it will be able to draw within 4 million miles of the surface—about as close as it can reasonably be expected to get without frying its instruments, hardy as they are.

Other News from the Cosmos

• Betelgeuse is brightening, leading astronomers to think it’s in the late stages of its core carbon-burning period—and could be ripe for supernova.

• The BOAT, or Brightest Of All Time explosion seen in the sky last October, was so bright in part because it was angled right at Earth and carried along a lot of stellar material.

• Cocoons of debris around massive dying stars may emit gravitational waves, which have previously only been detected around binary systems of black holes and neutron stars.

• Gravitational lensing, a phenomenon where the strong gravity of a foreground object magnifies the appearance of a more distant object, has been used to estimate the mass of galaxies containing quasars with much higher precision.

• The early universe was surprisingly riddled with supermassive galaxies containing upwards of 1B stars apiece due to the density of its star-forming regions, JWST observations revealed.

• Astronomers confirmed the existence of the faintest galaxy ever observed in the early universe.

• JWST spied complex organic molecules 12B light-years away from Earth.

• Spaceflight may cause fluid changes in the brains of astronauts that don’t return to normal even after many years back on the ground.

The View from Space

Astronaut Bruce McCandless II was born on this day in 1937, so we’re looking back on this iconic image from the STS-41B mission, on which McCandless performed the first untethered spacewalk. Here, he’s maneuvering himself with his hands while hovering a few meters away from the space shuttle Challenger.