The sweetest discovery

💥 Sugar found in space could help explain life's earliest beginnings.

with Ethan Siegel • July 25, 2026

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Greetings readers,

For me, one of the most exciting moments in science is when theoretical predictions and direct evidence — observational or experimental — finally come together to deliver a verdict on a speculative but profound idea. One longstanding prediction is that sugars, an essential ingredient and near-universal nutrient for all forms of life on Earth, should be formed in space. Another is that massive pairs of stars, typically born in binary systems, should go supernova one after another, leaving remnants that should be linked within the same complex across interstellar space. Excitingly, both predictions were recently validated with new, state-of-the-art observations. Erthyrulose, a four-carbon sugar, was just discovered close to the galactic center, and two supernova explosions were uncovered in the opposite direction: pointing away from the Milky Way’s core. It’s a big win for both ideas, as the observations validated the proposed ideas.

Other times, we only have some of the pieces in place for what we know how to predict, and there’s still a lot of guesswork involved in the ultimate resolution. From a terrestrial perspective, one such question is how spectacular this year’s upcoming Perseids are going to be. While they’re putting on a lousy show right now, by the time the peak arrives in the pre-dawn hours of August 13, the meteor shower should shape up to be the best of the year: a sight that nearly everyone on Earth should be able to enjoy. From a cosmic perspective, the positive, non-zero value to the energy of empty space itself raises the dreadful possibility that our Universe could quantum tunnel into a more stable state: triggering the catastrophic scenario of vacuum decay. I was recently asked if we should stop worrying about that scenario, given how large the Universe is and how unlikely we are to be affected by it anytime soon. And yet, because “worrying about it” leads to the possibility that we could actually prevent or delay it, I think worrying is immensely justified. Will you agree?

And finally, despite all of the advances we’ve made here in 2026, there are still some incredibly pervasive myths that lead many of us, despite our best intentions, to abandon science just when we need it most. There is a path back, however, and I hope the resources I’m providing can help you guide any close friends or family members back to evidence-based reality. As always, it’s my absolute pleasure to be sharing these stories with you week-after-week, with plenty more to come!

All the best,
Ethan

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SWEET BEGINNINGS

Sugar in space: another step toward life’s origins

Three types of molecules form the foundation of life as we know it: sugars, fats, and amino acids. While amino acids and nucleobases are common in meteorites and can be readily synthesized in prebiotic experiments, sugars have been far more elusive, making this latest discovery especially exciting. Because sugars are such an efficient energy source for even primitive life, they may have played a pivotal role in life's emergence on Earth and perhaps elsewhere. Here's what we've learned.

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SKY SHOW

2026’s Perseids, lousy this July, will peak at the perfect time

Each year, Earth passes through the same debris streams from the same comets and asteroids, giving rise to our recurring meteor showers. Some years favor the Quadrantids or Leonids, while the Geminids and Perseids are usually the most prolific. In 2026, however, one shower stands above the rest. Here’s why.

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ASK ETHAN

Ask Ethan: Should we stop worrying about vacuum decay?

Although dark energy appears consistent with a cosmological constant, its positive, non-zero value may not be the Universe’s true ground state, but only a false minimum. If that’s the case, it could someday transition to a lower-energy state, triggering the ultimate cosmic catastrophe: vacuum decay. Such a bubble of destruction would race outward at the speed of light, giving us no warning. Is there any reason to worry, or any possible way out?

If you have a burning question about the Universe,
email startswithabang@gmail.com!

MYTH BUSTER

4 myths cause us to abandon science. Here’s the path back.

There are many legitimate reasons to mistrust institutions, especially when corruption and bad behavior are easy to spot. But in recent years, public trust in science has eroded even around findings that are robust and undisputed. Here are four of the most common myths that “merchants of doubt” use to sow distrust, and how to see through them.

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EXPLOSIVE REUNION

A cosmic first: separated sibling stars reunited by supernovae

Stars are rarely born in isolation, but in large groups, with many ending up in binary or other multi-star systems. The highest-mass stars are especially likely to have similarly massive companions, and both are destined to die as supernovae. For the first time, astronomers have traced a new supernova remnant back to an older one in the same stellar family: the first-ever “supernova reunion” of long-separated sibling stars. Here’s what we know.

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Ethan Siegel, Ph.D., is an award-winning theoretical astrophysicist who's been writing Starts With a Bang since 2008. You can follow him on Twitter @StartsWithABang.

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