Why is the sky dark at night? Why isn’t it bright as day with starlight shining in every single direction? This is an old and surprisingly complex question, and it took modern physics to answer it. Two interrelated reasons account for it.
(Photo: NASA’s Hubble Space Telescope. Galaxy cluster Abell 370 contains several hundred galaxies tied together by the mutual pull of gravity.)
1. The universe is finite in both age and size. It began with the Big Bang about 14 billion years ago. The universe contains a limited number of stars, and since light takes time to travel, we can only see the ones that are less than 14 billion light years away. There just aren’t enough stars to fill the portion of the sky that we can see.
2. The universe is expanding fast in all directions, so everything is getting farther away from us. The farther away the receding source of the light is, the more stretched its wavelength is, and eventually the wavelength drops below our eyes’ threshold to see the light. In fact, the sky is not dark. It reverberates with the energy from the early universe, just after the Big Bang as matter coalesced, when the universe was very small, messy, and hard to understand. Special telescopes can detect these microwaves, but we can’t see them with our bare eyes.
Now, suppose we take this as a metaphor for life.
We are finite in time.
1. We were born. At first, we were small and messy.
2. We don’t remember our own birth because the threshold of our memory doesn’t go back that far. That’s good, since it was probably unpleasant.
We are finite in space.
3. We can’t observe everything. Knowledge is expanding in all directions faster than it can get to us. The internet more than proves that.
4. We wouldn’t understand everything anyway. Information can be stretched too thin to be intelligible. Again, the internet more than proves that.
The same science that explains the Big Bang does not yet know if the universe will end with a Big Freeze, Big Rip, Big Crunch, Big Bounce, or something completely different although equally Big.
5. We don’t know our own fate. That may be just as well, since it might not be especially entertaining.
6. Or maybe it will be entertaining. Cosmologist George Smoot, who won a Nobel Prize in Physics for his work to confirm the Big Bang Theory, made a special guest fanboy appearance on the television series Big Bang Theory. Scientists are great wags.
Our days are lit by one star, and the rest serve as little more than decoration in the night sky.
7. Half the time, we’re in the dark.
8. However, the darkness is sublimely decorated, and nothing can thrill our imaginations like staring up at the sky at night.
“Its actual name is ‘sheep catcher,’” she explained. “It would typically entangle wildlife around it and then hold on to it and unfortunately if they perish it would then give nutrients to the plant.”
“Plant-pollinator coevolution has been studied primarily by assessing the production and perception of visual and olfactory cues, even though there is growing evidence that both insects and plants can sense and produce, or transmit, vibroacoustic signals,” said Francesca Barbero, a professor of zoology at the University of Turin in Italy.
As magma moves upward through the Earth’s crust, it releases gases like carbon dioxide. Trees absorb this carbon dioxide, and in response, their leaves often grow more vibrant and healthy-looking. Using powerful tools like NASA’s Landsat 8 satellite, along with airborne instruments flown as part of the Airborne Validation Unified Experiment: Land to Ocean (AVUELO), scientists are now able to detect these subtle signs from above.
Dive into the wild world of weird plants! In this episode, the crew explores plant biology, carnivorous plants, zombie survival gardens, and Molly’s journey from forest explorer to plant store owner. Our goal is to have fun learning science through the lens of science fiction, fantasy, and pop-culture … and you’ll learn a few facts you can use to impress your friends at a party or use as a conversation starter to go down your own rabbit holes.
The construction industry faces pressure to be more sustainable. And the demand for greener buildings has led to a fresh look at wood construction. Wood is one of the oldest building materials used by mankind, but it does not have the strength needed to be used the load-bearing material in structures larger than houses and cabins.
A subjective plant map of 40 indoor plants based on plant impressions was prepared. The physical shapes of leaves were measured that could represent a subjective map. Both experts and people reported relaxation and liveliness on seeing plants. Plants with small leaves induced a sense of relaxation. Leaf shape classification may assist in selecting plants for indoor landscapes.
Often referred to as “broken tulips,” the striped variations of the popular flower were coveted in the 17th century for their beautiful markings. It’s been known since 1928 that the pattern is caused by a viral infection known as the tulip breaking virus, but exactly how the signature stripes are formed remained an unsolved mystery until now.
Artificial intelligence
I’m a member of the American Translators Association. The translation field is coping with neural machine translation (such as Google Translate) and AI translation:
The latest wave of artificial intelligence (AI), powered by large language models (LLM), is reshaping numerous professions, including the translation and interpreting industry. However, a growing reliance on AI highlights—not diminishes—the necessity of expert human linguists who possess the specialized skills to address translation and interpreting challenges that arise in this new context.… One of the greatest dangers of AI-generated translations and interpretations is that they may appear accurate to the general observer, making errors harder to detect for those without linguistic expertise.
On one hand, AI tools promise efficiency, personalization, and access. On the other, they provoke a deep discomfort. If students can simulate fluency and polish with a few prompts, what becomes of the messy, vulnerable, and transformative act of writing? What becomes of the human voice?
They describe trying to grade “hybrid essays half written by students and half written by robots,” trying to teach Spanish to kids who don’t know the meaning of the words they’re trying to teach them in English, and students who use AI in the middle of conversation. They describe spending hours grading papers that took their students seconds to generate: “I’ve been thinking more and more about how much time I am almost certainly spending grading and writing feedback for papers that were not even written by the student,” one teacher told me. “That sure feels like bullshit.”
It’ll be hard to talk about the whole Semiosis trilogy without some spoilers for the first two books, though I think I can communicate at least some of it in broad enough strokes. The overarching theme is sentience, and each book has its own tagline: “Sentience takes many forms.” “Sentience craves sovereignty.” “Sentience will prevail.”
Then I realized – or believe to have realized – that, while this book plays in an even more distant future than its precursors, its content, how it feels to me, is even closer to what is happening currently on planet Earth, and suddenly all disappointment disappeared, first to be replaced by some horror, as the book progressed, and then … by hope.
Semiosis 