GIF shows the impact window narrowing to exclude the moon

The Moon Is Safe, For Now: No Collision In 2032 After All

When Asteroid 2024 YR4 was first discovered, it created a bit of a kerfuffle when it was reported it had a couple-percent chance of hitting the Earth in 2032. At 60 meters (196 feet) across, this would have been in the “city killer” class that nobody really wants to see make landfall, so NASA and the ESA scrambled all assets to refine its trajectory in time to do something about it. Amongst those assets was the James Webb Space Telescope (JWST), which is now reporting it will miss both us and our moon.

Even with the JWST, asteroid 2024 YR4 only fills a few pixels.

We reported that JWST was being tapped for this task over a year ago, when the main concern was still if YR4 might hit Earth or not. An Earth impact was fairly quickly ruled out as the window narrowed to include only to Earth’s moon, and concern shifted to excitement. A city killer striking Earth is obviously bad news. The same thing happening to the Moon is a chance to do science — and 2032 would have been plenty of time to get assets in place to observe the impact.

Unfortunately for the impact-curious, JWST was able to narrow down the trajectory further — and we’ve now gone from up to a 4% chance of hitting Luna to a sure miss of 20,000 km or more.

As this game of cosmic billiards we call a solar system continues, it’s only a matter of time before Earth or her moon is struck by another object. Unless we can deflect it, that is — NASA and partnering agencies have been testing how to do that.

Life On K2-18b? Don’t Get Your Hopes Up Just Yet

Last week, the mainstream news was filled with headlines about K2-18b — an exoplanet some 124 light-years away from Earth that 98% of the population had never even heard about. Even astronomers weren’t aware of its existence until the Kepler Space Telescope picked it out back in 2015, just one of the more than 2,700 planets the now defunct observatory was able to identify during its storied career. But now, thanks to recent observations by the James Web Space Telescope, this obscure planet has been thrust into the limelight by the discovery of what researchers believe are the telltale signs of life in its atmosphere.

Artist’s rendition of planet K2-18b.

Well, maybe. As you might imagine, being able to determine if a planet has life on it from 124 light-years away isn’t exactly easy. We haven’t even been able to conclusively rule out past, or even present, life in our very own solar system, which in astronomical terms is about as far off as the end of your block.

To be fair the University of Cambridge’s Institute of Astronomy researchers, lead by Nikku Madhusudhan, aren’t claiming to have definitive proof that life exists on K2-18b. We probably won’t get undeniable proof of life on another planet until a rover literally runs over it. Rather, their paper proposes that abundant biological life, potentially some form of marine phytoplankton, is one of the strongest explanations for the concentrations of dimethyl sulfide and dimethyl disulfide that they’ve detected in the atmosphere of K2-18b.

As you might expect, there are already challenges to that conclusion. Which is of course exactly how the scientific process is supposed to work. Though the findings from Cambridge are certainly compelling, adding just a bit of context can show that things aren’t as cut and dried as we might like. There’s even an argument to be made that we wouldn’t necessarily know what the signs of extraterrestrial life would look like even if it was right in front of us.

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NASA Taps Webb To Help Study 2032 Asteroid Threat

In all likelihood, asteroid 2024 YR4 will slip silently past the Earth. Based on the data we have so far, there’s an estimated chance of only 2.1% to 2.3% that it will collide with the planet on December 22nd, 2032. Under normal circumstances, if somebody told you there was a roughly 98% chance of something not happening, you probably wouldn’t give it a second thought. There’s certainly a case to be made that you should feel that way in regards to this particular event — frankly, it’s a lot more likely that some other terrible thing is going to happen to you in the next eight years than it is an asteroid is going to ruin your Christmas party.

That being said, when you consider the scale of the cosmos, a 2+% chance of getting hit is enough to raise some eyebrows. After all, it’s the highest likelihood of an asteroid impact that we’re currently aware of. It’s also troubling that the number has only gone up as further observations of 2024 YR4’s orbit have been made; a few weeks ago, the impact probability was just 1%. Accordingly, NASA has recently announced they’ll be making time in the James Webb Space Telescope’s busy scientific schedule to observe the asteroid next month.

So keeping in mind that we’re still talking about an event that’s statistically unlikely to actually occur, let’s take a look at what we know about 2024 YR4, and how further study and analysis can give us a better idea of what kind of threat we’re dealing with.

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Lagrange Points And Why You Want To Get Stuck At Them

Visualization of the Sun-Earth Lagrange points.

Orbital mechanics is a fun subject, as it involves a lot of seemingly empty space that’s nevertheless full of very real forces, all of which must be taken into account lest one’s spacecraft ends up performing a sudden lithobraking maneuver into a planet or other significant collection of matter in said mostly empty space. The primary concern here is that of gravitational pull, and the way it affects one’s trajectory and velocity. With a single planet providing said gravitational pull this is quite straightforward to determine, but add in another body (like the Moon) and things get trickier. Add another big planetary body (or a star like our Sun), and you suddenly got yourself the restricted three-body problem, which has vexed mathematicians and others for centuries.

The three-body problem concerns the initial positions and velocities of three point masses. As they orbit each other and one tries to calculate their trajectories using Newton’s laws of motion and law of universal gravitation (or their later equivalents), the finding is that of a chaotic system, without a closed-form solution. In the context of orbital mechanics involving the Earth, Moon and Sun this is rather annoying, but in 1772 Joseph-Louis Lagrange found a family of solutions in which the three masses form an equilateral triangle at each instant. Together with earlier work by Leonhard Euler led to the discovery of what today are known as Lagrangian (or Lagrange) points.

Having a few spots in an N-body configuration where you can be reasonably certain that your spacecraft won’t suddenly bugger off into weird directions that necessitate position corrections using wasteful thruster activations is definitely a plus. This is why especially space-based observatories such as the James Webb Space Telescope love to hang around in these spots.

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Timeline of the universe. A representation of the evolution of the universe over 13.77 billion years. The far left depicts the earliest moment we can now probe, when a period of "inflation" produced a burst of exponential growth in the universe. (Size is depicted by the vertical extent of the grid in this graphic.) For the next several billion years, the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity. More recently, the expansion has begun to speed up again as the repulsive effects of dark energy have come to dominate the expansion of the universe. The afterglow light seen by WMAP was emitted about 375,000 years after inflation and has traversed the universe largely unimpeded since then. The conditions of earlier times are imprinted on this light; it also forms a backlight for later developments of the universe. (Credit: NASA)

ESA’s Euclid Space Telescope And The Quest For Dark Energy

Most of what humankind and other mammalian species on Earth experience of the Universe is primarily restricted to the part of the electromagnetic spectrum which our optical organs can register. Despite these limitations, we have found ways over the centuries which enable us to perceive the rest of the EM spectrum, to see both what is incredibly far away, and what is incredibly small, to constantly get a little bit closer to understanding what makes the Universe into what we can observe today, and what it may look like in the future.

An essential element of this effort are space telescopes, which gaze into the depths of the Universe with no limitations imposed by the Earth’s atmosphere, or human activity. Among the many uses of space telescopes, the investigation of the expansion of the Universe is perhaps the most fascinating, as this brings us ever closer to the answers to the most fundamental questions about not only its shape, but also to its future, which may include hitherto unknown types of matter and energy.

With the recently launched Euclid space telescope, another chapter is being opened in the saga on dark energy and matter, and their nature and effects on the Universe, as well as whether they exist at all. Yet how exactly do you use a space telescope to ferret out the potential effects of dark energy?

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3D Printing Blueprints And Other Wall Art

Today if you want to reproduce a big schematic or a mechanical drawing, you just ask it to print or plot from the CAD model. But back in the day, you drew on big sheets at a drafting table. How do you make copies? Sure, there were a few large-format copiers, but they were expensive. A more common method was to use a heliographic copier which, often but not always, resulted in a blueprint — that is a blue page with white lines or vice versa. These days, you are more likely to see a blueprint as an artistic wall hanging, and since [Basement Creations] wanted some, he figured out how to make them with a 3D printer.

These prints aren’t really blueprints. They use the printer as a plotter and deposit white ink on a blue page. In the video below, he shows a number of ways to use a printer to create interesting wall art, even if you want it to be bigger than the print bed. Some of the wall art uses multiple 3D printed parts, and others use the printer as a plotter.

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Hackaday Links: March 26, 2023

Sad news in the tech world this week as Intel co-founder Gordon Moore passed away in Hawaii at the age of 94. Along with Robert Noyce in 1968, Moore founded NM Electronics, the company that would later go on to become Intel Corporation and give the world the first commercially available microprocessor, the 4004, in 1971. The four-bit microprocessor would be joined a few years later by the 8008 and 8080, chips that paved the way for the PC revolution to come. Surprisingly, Moore was not an electrical engineer but a chemist, earning his Ph.D. from the California Institute of Technology in 1954 before his postdoctoral research at the prestigious Applied Physics Lab at Johns Hopkins. He briefly worked alongside Nobel laureate and transistor co-inventor William Shockley before jumping ship with Noyce and others to found Fairchild Semiconductor, which is where he made the observation that integrated circuit component density doubled roughly every two years. This calculation would go on to be known as “Moore’s Law.”

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