Complex Organic Chemistry In Sulfuric Acid And Life On Venus

March 25, 2024 by Maya Posch 25 Comments

Finding extraterrestrial life in any form would be truly one of the largest discoveries in humankind’s history, yet after decades of scouring the surface of Mars and investigating other bodies like asteroids, we still have found no evidence. While we generally assume that we’re looking for carbon-based lifeforms in a water-rich environment like Jupiter’s moon Europa, what if complex organic chemistry would be just as happy with sulfuric acid (H₂SO₄) as solvent rather than dihydrogen monoxide (H₂O)? This is the premise behind a range of recent studies, with a newly published research article in Astrobiology by [Maxwell D. Seager] and colleagues lending credence to this idea.

Previous studies have shown that organic chemistry in concentrated sulfuric acid is possible, and that nucleic acid bases – including adenosine, cytosine, guanine, thymine and uracil which form DNA – are also stable in this environment, which is similar to that of the Venusian clouds at an altitude where air pressure is roughly one atmosphere. In this new article, twenty amino acids were exposed to the concentrations of sulfuric acid usually found on Venus, at 98% and 81%, with the rest being water. Of these, 11 were unchanged after 4 weeks, 9 were reactive on their side chains, much like they would have been in pure water. Only tryptophan ended up being unstable, but as the researchers note, not all amino acids are stable in water either.

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The Hunt For Alien Radio Signals Began Sooner Than You Think

March 20, 2024 by Lewin Day 22 Comments

Every 26 months, Earth and Mars come tantalizingly close by virtue of their relative orbits. The closest they’ve been in recent memory was a mere 55.7 million kilometers, a proximity not seen in 60,000 years when it happened in 2003.

However, we’ve been playing close attention to Mars for longer than that. All the way back in 1924, astronomers and scientists were contemplating another close fly by from the red planet. With radio then being the hot new technology on the block, the question was raised—should we be listening for transmissions from fellows over on Mars?

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The Greenhouse Effect Isn’t For Greenhouses

March 19, 2024 by Lewin Day 22 Comments

Think of a greenhouse. It’s a structure with glass walls that lets light in and traps heat, all for the benefit of the plants inside. As for how it works, that’s elementary! It’s all down to the greenhouse effect… right?

Alas, no. So many of us have been mislead. Let’s rexamine how we think greenhouses work, and then explore what’s actually going on.
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A Simple Seismometer You Can Build Yourself

March 16, 2024 by Lewin Day 9 Comments

If you’re a child, there are certain things you’re taught even though they’re probably not directly relevant to your life. We teach young kids all about dinosaurs, and we teach older kids all about how the mitochondria is the powerhouse of the cell. We also teach kids about natural phenomena like earthquakes, and the equipment used to measure them. Namely, seismometers. You might like to satisfy your own child-like curiosity by building one of your own, like [mircemk] did.

Output from the build showing tremors in the Earth.

The build starts with a sensitive geophone of [mircemk’s] own design. That’s basically a microphone but it’s for picking up vibrations in the ground, not in the air. However, a geophone is not enough. You need to be able to pick up the signals from the geophone and then plot them if you want a seismometer.

First, the signals from the geophone must be amplified, which is achieved with a small circuit based around the LM358 op-amp. From there, the signal is sent to an Arduino where the output is captured via the analog-to-digital converter. This passes the signal to an attached PC which plots the results using a piece of software called NERdaq, which was developed for schools that built their own slinky-based seismometers.

[mircemk] reports that this setup has served as a reliable tool for visualizing earthquake activity for over 6 years. Though, it bears noting, it’s not calibrated so don’t expect to get science grade results out of it. Regardless, though, it’s a super cool way to understand more about what is going on with the geology around us. Video after the break.

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Gentle Introduction To White Light Interferometry

March 13, 2024 by Maya Posch 3 Comments

Screenshot of the Zygo white light interferometry microscope software. (Credit: Huygens Optics)

White light interferometry (WLI) is a contact-free optical method for measuring surface height. It uses the phase difference between the light reflected off a reference mirror and the target sample to calculate the height profile of the sample’s surface. As complex as this sounds, it doesn’t take expensive hardware to build a WLI microscope, as [Huygen Optics] explains in a detailed introductory video on the topic. At its core you need a source of white light (e.g. a white LED), with a way to focus the light so as to get a spatially coherent light source, like aluminium foil with a pin hole and a lens.

This light source then targets a beam splitter, which splits the light into one beam that targets the sample, and one that targets the reference mirror. When both beams are reflected and return to the beam splitter, part of the reflected light from either side ends up at the camera, which captures the result of the reference and sample beams after their interference (i.e. combination of the amplitudes). This creates a Michelson interferometer, which is simple, but quite low resolution. For the demonstrated Zygo Newview 100 WLI microscope this is the first objective used, followed by a more recent innovation: the Mirau interferometer, which integrates the reference mirror in such a manner that much higher resolutions are possible, down to a few µm.

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An Optical Computer Architecture

March 12, 2024 by Al Williams 14 Comments

We always hear that future computers will use optical technology. But what will that look like for a general-purpose computer? German researchers explain it in a recent scientific paper. Although the DOC-II used optical processing, it did use some conventional electronics. The question is, how can you construct a general computer that uses only optical technology?

The paper outlines “Miller’s criteria” for practical optical logic gates. In particular, any optical scheme must provide outputs suitable for introduction to another gate’s inputs and also support fan out of one output to multiple inputs. It is also desirable that each stage does not propagate signal degradation and isolate its outputs from its inputs. The final two criteria note that practical systems don’t depend on loss for information representation since this isn’t reliable across paths, and, similarly, the gates should require high-precision adjustment to work correctly.

The paper also identifies many misconceptions about new computing devices. For example, they assert that while general-purpose desktop-class CPUs today contain billions of devices, use a minimum of 32-bits of data path, and contain RAM, this isn’t necessarily true for CPUs that use different technology. If that seems hard to believe, they make their case throughout the paper. We can’t remember the last scientific paper we read that literally posed the question, “Will it run Doom?” But this paper does actually propose this as a canonical question.

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3D Imaging For Natural Science — For Free

March 11, 2024 by Al Williams 4 Comments

It isn’t that unusual for a home lab to have a microscope, but wouldn’t it be cool to have a CT scanner? Well, you probably won’t anytime soon, but if you are interested in scans of vertebrates — you know, animals with backbones — a group of museums have you covered.

The oVert project is scanning 20,000 specimens and making the results available to everyone. This should be a boon to educators and might even be useful for 3D printing animal forms. Check out the video about the project below.

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