Japan is the fifth country to land on the moon (at least, we think!)

Japan has reached the moon!! Whether the landing was considered successful is a little more unclear, but it LOOKS to be a success. Here’s what happened.

This morning, on January 19 around 10:20 am ET, I THINK Japan successfully soft landed an uncrewed spacecraft on the moon. The spacecraft, SLIM, or Smart Lander for Investigating the Moon, is intact, it’s currently receiving and responding to signals, and the two rovers LEV1 and LEV2 have successfully deployed. BUT. Unfortunately, the lander’s solar cells aren’t generating power, so the spacecraft is currently running on battery power.

Despite the solar cells, I do think this IS a successful landing. It’s not clear exactly what the problem with the solar panels is, though there’s speculation that the lander rolled after landing. (There was some concern that the lander toppled over — that was actually supposed to happen according to the mission briefing.)

Screenshot from the livestream of the lander on the moon

But it may have changed position or rolled after falling over, which could be the challenge with the solar panels — basically they’re at the wrong angle to gather sunlight and generate power. JAXA has made clear they are prioritizing data retrieval and downloading images over troubleshooting the solar cells, as they have several hours of battery life. They will continue trying the solar cells in two weeks as the sun changes angles thanks to the moon’s rotation (which makes the issue sound like a solar panel orientation and direction issue, but the flip side is the craft has to survive the extremely cold lunar nights) — JAXA did make clear that they don’t think the spacecraft damaged the solar panel on landing or fell on the solar panels and damaged them. It’s not a hardware issue.

JAXA did release the minimum success criteria before the mission launched, which is soft landing of the SLIM spacecraft by using vision-based landing. They achieved that. Officials at the organization do also think they achieved the precision landing within 100 m of their target, but it will take a month or so to confirm. Being able to do things on the moon after landing is extra, and they’re even going to be able to do that.

SLIM didn’t burn up in Earth’s atmosphere (sorry Peregrine), it didn’t slam into the moon, but it doesn’t have working solar panels. Is this a success? JAXA is making clear that they think it is. The reason it matters because if the SLIM landing is considered a success, that would make Japan the fifth country to successfully land on the moon, after the US, former Soviet Union, China, and India.

I personally consider this a success. Being able to land a craft on the moon with that kind of precision is very cool, and the systems worked during descent. Engines fired when they were supposed to, the spacecraft didn’t crash into the moon’s surface. We’re receiving telemetry from the spacecraft, and the rovers are exploring the surface (and they have independent communication capability so even if JAXA is unable to generate power, they will continue to explore and send back data.) They’re going to continue working the problem and we should get more information in the next few days and weeks.

It’s not my decision, but I’m calling this one a win.

Main source for this video: JAXA press conference

Scientists solved a cosmic mystery from the early universe

Scientists shouldn't be able to detect a specific type of light, Lyman-α (or Lyman alpha), from the earliest stars and galaxies, but they can. A team using JWST data has finally figured out the answer to this ongoing mystery.

Scientists may have found the answer to a huge mystery about the early universe, thanks to JWST.

The answer to this mystery lies in this photo, which focuses on a specific type of light called Lyman-α. Scientists think Lyman-α was abundant in the early universe, produced by vigorous star and galaxy formation. But we shouldn’t actually be able to detect it. That’s because there was a lot of dense neutral hydrogen surrounding these early galaxies, which should have absorbed and scattered this kind of light — but they have been able to detect this Lyman-α emission. Now we know why, thanks to JWST’s NIRCam or near-infrared camera. The answer is galaxies, and the research was published in Nature Astronomy.

Here’s what’s going on.

Remember that looking deep into the universe is also like looking back in time because of how long the light takes to reach us. When we’re peering into the darkest depths of the universe, thanks to JWST’s infrared optimization, we’re also looking back in time to the early universe.

We’re focusing here on what’s called the epoch of reionization. We don’t know exactly when this era started, but scientists think it ended about 12.8 billion years ago (that would be a billion years after the Big Bang).

Before this period started, the universe was in what we call the “dark ages” — meaning it was literally dark. Dense neutral hydrogen gas distributed throughout the early universe meant the universe was opaque — basically, you couldn’t see through it. Think of straining to see the stars in the sky on a cloudy night. This is what the entire universe looked like.

Reionization is basically when the universe became see through. This occurred when the neutral hydrogen became dense enough in areas to collapse into the first stars and galaxies. This is part the process that scientists think ionized the universe (though it’s still unclear exactly how this happened and what galaxies contributed to the process). Once the epoch of reionization was complete, the universe looked much like it did today, with light able to freely travel through it.

This is all part of why it is so challenging to see light from the early universe, and why an infrared-optimized telescope is so important to detecting the earliest stars and galaxies — during the era of reionization, visible and UV light didn’t always travel freely through the universe, but infrared light still did.

Okay, so now let’s get back to the central issue — Lyman-α light. Before the epoch of reionization ended, that neutral hydrogen surrounding these early stars and galaxies should have blocked Lyman-α light. But it hasn’t. And now scientists know that galaxies are responsible.

Previously, scientists were able to detect the largest and brightest galaxies from this time, thanks to observatories like Hubble. This is where they detected Lyman-α emission, but now thanks to both the angular resolution and sensitivity of JWST, they have found that these large galaxies are not, in fact surrounded just by dense neutral hydrogen. JWST was able to detect smaller, fainter galaxies surrounding the larger ones, while HUbble was only able to detect single large galaxies. You can see that here in this image — this is the galaxy EGSY8p7, as taken by Hubble. This is how it looked when the universe was approximately 600 million years old.

Now here’s the JWST photo. You can see the central galaxy here, along with two very close companion galaxies. This image was captured with seven different near-infrared filters.

These galaxies are interacting and merging with one another, and star formation was happening at a frenetic pace. This star formation and galaxy interaction and mergers is what was able to clear hydrogen and allow the abundant Lyman-α emissions to escape.