Science

1129 Articles

Measuring The Mighty Roar Of SpaceX’s Starship Rocket

November 21, 2024 by 46 Comments

SpaceX’s Starship is the most powerful launch system ever built, dwarfing even the mighty Saturn V both in terms of mass and total thrust. The scale of the vehicle is such that concerns have been raised about the impact each launch of the megarocket may have on the local environment. Which is why a team from Brigham Young University measured the sound produced during Starship’s fifth test flight and compared it to other launch vehicles.

Published in JASA Express Letters, the paper explains the team’s methodology for measuring the sound of a Starship launch at distances ranging from 10 to 35 kilometers (6 to 22 miles). Interestingly, measurements were also made of the Super Heavy booster as it returned to the launch pad and was ultimately caught — which included several sonic booms as well as the sound of the engines during the landing maneuver.

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Simple Hydrogen Generator Makes Bubbles And Looks Cool

November 21, 2024 by 18 Comments

Hydrogen! It’s a highly flammable gas that seems way too cool to be easy to come by. And yet, it’s actually trivial to make it out of water if you know how. [Maciej Nowak] has shown us how to do just that with his latest build.

The project in question is a simple hydrogen generator that relies on the electrolysis of water. Long story short, run a current through water and you can split H2O molecules up and make H2 and O2 molecules instead. From water, you get both hydrogen to burn and the oxygen to burn it in! Even better, when you do burn the hydrogen, it combines with the oxygen to make water again! It’s all too perfect.

This particular generator uses a series of acrylic tanks. Each is fitted with electrodes assembled from threaded rods to pass current through water. The tops of the tanks have barbed fittings which allow the gas produced to be plumbed off to another storage vessel for later use. The video shows us the construction of the generator, but we also get to see it in action—both in terms of generating gas from the water, and that gas later being used in some fun combustion experiments.

Pedants will point out this isn’t really just a hydrogen generator, because it’s generating oxygen too. Either way, it’s still cool. We’ve featured a few similar builds before as well.

(Pedantic editor’s note: Because this build doesn’t separate the H2 from the O2, what you get is a stoichiometric mix, or HHO, or “Oxyhydrogen“. By virtue of being in exactly the right ratio to combust, this stuff is significantly more explosive than pure H2. Be careful!)

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Most Extreme Hypergravity Facility Starts Up In China With 1,900 Times Earth’s Gravity

November 19, 2024 by 33 Comments
The schematic diagram of the experimental centrifuge. (Credit: Jianyong Liu et al., 2024)
The schematic diagram of the experimental centrifuge. (Credit: Jianyong Liu et al., 2024)

Recently China’s new CHIEF hypergravity facility came online to begin research projects after beginning construction in 2018. Standing for Centrifugal Hypergravity and Interdisciplinary Experiment Facility the name covers basically what it is about: using centrifuges immense acceleration can be generated. With gravity defined as an acceleration on Earth of 1 g, hypergravity is thus a force of gravity >1 g. This is distinct from simple pressure as in e.g. a hydraulic press, as gravitational acceleration directly affects the object and defines characteristics such as its effective mass. This is highly relevant for many disciplines, including space flight, deep ocean exploration, materials science and aeronautics.

While humans can take a g-force (g0) of about 9 g0 (88 m/s2) sustained in the case of trained fighter pilots, the acceleration generated by CHIEF’s two centrifuges is significantly above that, able to reach hundreds of g. For details of these centrifuges, this preprint article by [Jianyong Liu] et al. from April 2024 shows the construction of these centrifuges and the engineering that goes into their operation, especially the aerodynamic characteristics. Both air pressure (30 – 101 kPa) and arm velocity (200 – 1000 g) are considered, with the risks being overpressure and resonance, which if not designed for can obliterate such a centrifuge.

The acceleration of CHIEF is said to max out at 1,900 gravity tons (gt, weight of one ton due to gravity), which is significantly more than the 1,200 gt of the US Army Corps of Engineers’ hypergravity facility.

Crowdsourcing Ionosphere Data With Phones

November 18, 2024 by 19 Comments

How do you collect a lot of data about the ionosphere? Well, you could use sounding rockets or specialized gear. Or maybe you can just conscript a huge number of cell phones. That was the approach taken by Google researchers in a recent paper in Nature.

The idea is that GPS and similar navigation satellites measure transit time of the satellite signal, but the ionosphere alters the propagation of those signals. In fact, this effect is one of the major sources of error in GPS navigation. Most receivers have an 8-parameter model of the ionosphere that reduces that error by about 50%.

However, by measuring the difference in time between signals of different frequencies, the phone can estimate the total electron current (TEC) of the ionosphere between the receiver and the satellite. This requires a dual-frequency receiver, of course.

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The Laser Shadow Knows

November 18, 2024 by 31 Comments

Normally, you think of things casting a shadow as being opaque. However, new research shows that under certain conditions, a laser beam can cast a shadow. This may sound like nothing more than a novelty, but it may have applications in using one laser beam to control another. If you want more details, you can read the actual paper online.

Typically, light passes through light without having an effect. But using a ruby crystal and specific laser wavelengths. In particular, a green laser has a non-linear response in the crystal that causes a shadow in  a blue laser passing through the same crystal.

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The Diablo Canyon NPP in California. This thermal plant uses once-through cooling. (Credit: Doc Searls)

US DOE Sets New Nuclear Energy Targets

November 14, 2024 by 63 Comments

To tackle the growing electrification of devices, we’ll need to deploy more generation to the grid. The US Department of Energy (DOE) has unveiled a new target to triple nuclear generating capacity by 2050.

Using a combination of existing Generation III+ reactor designs, upcoming small modular and micro reactors, and “legislation like the ADVANCE Act that streamlines regulatory processes,” DOE plans to add 35 gigawatt (GW) of generating capacity by 2035 and an additional 15 GW installed per year by 2040 to hit a total capacity of 200 GW of clean, green atom power by 2050.

According to the DOE, 100 GW of nuclear power was deployed in the 1970s and 1980s, so this isn’t an entirely unprecedented scale up of nuclear, although it won’t happen overnight. One of the advantages of renewables over nuclear is the lower cost and better public perception — but a combination of technologies will create a more robust grid than an “all of your eggs in one basket” approach. Vehicle to grid storage, geothermal, solar, wind, and yes, nuclear will all have their place at the clean energy table.

If you want to know more about siting nuclear on old coal plants, we covered DOE’s report on the matter as well as some efforts to build a fusion reactor on a decommissioned coal site as well.

Microfluidic Motors Could Work Really Well For Tiny Scale Tasks

November 14, 2024 by 8 Comments

The vast majority of motors that we care about all stick to a theme. They rely on the electromagnetic dance between electrons and magnets to create motion. They come in all shapes and sizes and types, but fundamentally, they all rely on electromagnetic principles at heart.

And yet! This is not the only way to create a motor. Electrostatic motors exist, for example, only they’re not very good because electrostatic forces are so weak by comparison. Only, a game-changing motor technology might have found a way to leverage them for more performance. It achieves this by working with fluid physics on a very small scale.

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