Blog

Apr 27, 2024

This Week in Space: Sunspots, the Two Towers, and the G

Hello, friends, and welcome back to This Week in Space. We've got plenty of updates from NASA and news on a possible fifth force of nature. Plus, astronomers announced this week that the JWST has

Hello, friends, and welcome back to This Week in Space. We've got plenty of updates from NASA and news on a possible fifth force of nature. Plus, astronomers announced this week that the JWST has confirmed the age of the oldest galaxy ever discovered, which formed within a few hundred million years after the Big Bang.

Scientists from Fermilab have announced new results from a years-long experiment that, if confirmed, would rewrite the laws of physics.

We currently know of four fundamental forces: gravity, electromagnetism, the strong nuclear force which holds together the nuclei of atoms, and the weak nuclear force that drives radioactive decay. Physicists use a shortlist of rules called the Standard Model to describe how these forces act on different types of particles.

It's known that the Standard Model has holes in it: places where its predictions don't adequately explain the results we see in the world. One such place is the behavior of muons, which have negative charges like electrons but are about 200 times as massive. In magnetic fields, muons wiggle or "gyrate" at a speed called the g-factor. However, Fermilab muon-beam experiments have consistently found muons' g-factor to be smaller than the Standard Model predicts—by a margin too large to ignore. Their conclusion? There must be something other than the electromagnetic force acting on muons: a new, fundamental force of nature.

Last November, when the Artemis I mission launched, the SLS became the most powerful rocket ever to reach orbit. But all that power comes with a price. Mobile launcher 1 (ML-1) sustained significant damage during the Artemis launch, and the two hurricanes that followed in quick succession didn't help. The tower has been in the Vehicle Assembly Building ever since, undergoing repairs and upgrades in preparation for its reuse with Artemis II, which will have humans aboard. Wednesday at the Kennedy Space Center, NASA loaded the 380-foot-tall structure onto a crawler-transporter, beginning the mobile launch tower's two-day return trip to Launch Pad 39-B.

That same day at the KSC, the agency also began construction on a second, even bigger mobile launcher, ML-2. When it's finished, ML-2 will weigh more than 11 million pounds, and it'll be 10 feet taller than ML-1. For Artemis IV the SLS will trade out upper stages, switching to a larger, sturdier fuel tank (and a bigger, less-janky CubeSat launcher). ML-2 is designed to accommodate that difference in height, as well as a future version of the SLS called Block 2. Meanwhile, NASA hopes to start stacking up ML-1 with the Artemis II spacecraft in early 2024.

Late Wednesday night, SpaceX launched another batch of Starlink satellites from Canaveral. Starlink and other telecom satellite constellations are launching in part to clear out the Ka-band per FCC order, in advance of 5G network deployment—but at least one important Ka-band user will have to stay after class. NASA's Deep Space Network uses that signal band to communicate with the James Webb Space Telescope.

Right now, Webb is something of a scientific darling. It's been operating for about a year now, with a mile-long queue for telescope time. All that research, meanwhile, generates a steady stream of beautiful space images. Here's what the Webb telescope has been up to this week.

Barnard's Galaxy is a dwarf galaxy about 7,000 light-years across. It's about 1.6 million light-years from us, but that's no problem for Webb, which regularly observes targets thousands of times farther away. In a new composite, Webb scientists combine MIRI and NIRCam readings from the same patch of sky to illustrate Barnard's galaxy in remarkable detail.

MIRI can resolve the veil of gas around Barnard's Galaxy, while NIRCam excels at imaging the surrounding starfield.

Last year, Webb astronomers from the University of Texas at Austin spied Maisie's Galaxy, a celestial object so distant it's a wonder we can see it at all. At the time, they estimated that this unassuming blob was among the most distant (and therefore oldest) objects we'd ever found. New observations, also from the JWST, confirm it. Maisie's Galaxy has a redshift of z=11.4, which means the light Webb picked up when it took this image was emitted less than 400 million years after the Big Bang.

Maisie's Galaxy was named for the daughter of UT Austin astronomer Steven Finkelstein since the galaxy was discovered on her birthday.

The hunt for exoplanets is a delicate business. It's gotten easier in recent years, thanks to instruments like the Kepler Space Telescope and TESS, but there are still some major hurdles we're only starting to learn our way around. One issue is that a surprising number of exoplanets are so-called "hot Jupiters," which are gas giants (frequently very large) that orbit very close to their stars. Washed out and drowned in the light of their stars, hot Jupiters are tough to study—but astronomers might have found a test case in a binary star system called WD 0032–317. It's host to an enormous planet that's even hotter—and brighter—than the Sun.

The brown dwarf in WD 0032–317 glows so brightly because it's being bombarded with radiation by its companion white dwarf. On the day side, temperatures soar to 14,000 degrees Fahrenheit (7,700 degrees Celsius). Even the planet's night side is hotter than the Sun. For a sense of scale, the highest known melting temperature of any material is that of a tantalum-hafnium-carbide alloy that turns to liquid hellfire at a mere 4,000 degrees Celsius or so.

“Hot Jupiters are the antithesis of habitable planets—they are dramatically inhospitable places for life,” said Dr. Na’ama Hallakoun, lead author of a study describing the system. “Future high-resolution spectroscopic observations of this hot Jupiter-like system—ideally made with NASA’s new James Webb Space Telescope—may reveal how hot, highly irradiated conditions impact atmospheric structure, something that could help us understand exoplanets elsewhere in the universe.”

In 1769, Scottish astronomer Alexander Wilson noticed that sunspots became foreshortened as they crossed the face of the Sun. This foreshortening led Wilson to discover that the sunspots appeared to be sunken or depressed toward the middle, a phenomenon we named after him: the Wilson effect. Tuesday, high in the French Alps, an amateur astronomer named Thierry Legault vindicated Wilson's legacy, capturing the Wilson effect with astonishing clarity.

"The sunspot's umbra is lower than the average solar surface, with surrounding penumbral filaments dipping down into it," Legault said. "The filaments are visible on the far edge of the 'bowl,' but not on the near edge, highlighting the depression."

Just a few days ago, another amateur astronomer in Japan discovered a new comet that may become a naked-eye object next month. When Hideo Nishimura spotted Comet C/2023 P1 (which I vote we call Nishimura's Comet), it was as faint as a 10th-magnitude star. The newfound point of light may be a hyperbolic comet, hurtling through space with so much energy that the Sun won't capture it even though it will pass by the Sun inside the orbit of Mercury. If so, this will be the one and only time to see it. But forecasters believe that Nishimura's Comet will become more than a hundred times as bright, reaching magnitude 3 as it buzzes past the Sun in mid-September. If it does, it will be visible to the naked eye in rural areas.

August was a rare month, in that it features not one but two supermoons, the latter of which is also a blue Moon. Blue Moons happen because calendar months are longer than lunar months. Happily, that means that this time next month will be right around the next new Moon—good news for aspiring comet-watchers.

Here are the phases of the Moon for the rest of August:

See you next week!