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Category: space

Does Entropy Control Time?

In this episode, Neil deGrasse Tyson and Chuck Nice speak with physicist Sean Carroll about whether entropy actually creates time. Sean explains that entropy does not generate time itself, but it gives time an arrow—a direction from past to future. Even if the universe were to stop expanding and begin collapsing, entropy would still increase. The key distinction is between time (which can exist without direction) and the arrow of time, which entropy provides through statistical mechanics and phase space dynamics.

From ‘The Complex Universe, with Sean Carroll’: • The Complex Universe, with Sean Carroll.

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What Is Beyond The End?

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Written by Colin Stuart.
Check out his fantastic astronomy newsletter here: https://colinstuart.substack.com.

Edited and animated by Siji Sheehan.
Narrated by David Kelly.
Thumbnail Art by Ettore Mazza.
Audio editing by Jack White and Peter Halstead.
Mastering by Craig Stevenson.
Extra animations by @ArtandContext (Manuel Rubio)
Extra animations by Jero Squartini https://www.fiverr.com/share/0v7Kjv using Manim — MIT License, © 2020–2023 3Blue1Brown LLC

A huge thanks to our Ho’oleilana Patreon supporters — James Keller, Unpunnyfuns, Ramsay Chambers, Matthew Williams and Mike Cumings, Jr.

Footage from Videoblocks, Artlist. Other footage from NASA and ESO.
Music from Epidemic Sound, Artlist, Silver Maple and Yehezkel Raz.
Images of scientists frequently from the AIP
Icons from The Noun Project.
Quantum Fluctuations by Derek Leinweber.

00:00 Introduction.
04:18 Will The Universe Go On Forever?
17:42 What Lingers In The Long Night?
33:20 What Would It Mean?
46:20 Everything Everywhere

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Using moon dirt with 3D printing to build future lunar colonies

Simulated lunar dirt can be turned into extremely durable structures, potentially paving the way to more sustainable and cost-effective space missions, a new study suggests. Using a special laser 3D printing method, researchers melted fake lunar soil—a synthetic version of the fine dusty material on the moon surface, called regolith simulant—into layers and fused it with a base surface to manufacture small, heat-resistant objects.

If utilized on the lunar surface, the material may help build sturdy, nontoxic habitats and tools for future astronauts, capabilities that would be vital to the NASA Artemis missions that aim to establish a long-term human presence on the moon by the end of the decade.

But to assess how well this new construction material may work in space, the team tested their fabrication process under a range of different environmental conditions, revealing that the overall quality of the material depends greatly on the surface onto which the soil is printed.

10 Ancient Space Objects That Existed Before the Universe Itself

All right, let’s go.
Number 10. Methuselah’s Star.
In 2000, a team of astronomers led by Howard Bond at Penn State University pointed the Hubble Space Telescope at a faint star in the constellation Libra and made a discovery that should have been impossible. The star, designated HD 140,283 and later nicknamed Methuselah, appeared to be 14.5 billion years old. The universe itself is only 13.8 billion years old. A star older than the cosmos that contains it shouldn’t exist. Yet there it was, burning quietly just 190 light years from Earth, defying the most fundamental timeline in all of physics.

Space-grade perovskite solar cells can survive extreme temperature fluctuations

The Aydin Group at LMU Munich has unveiled a novel strategy for making perovskite solar cells more robust against extreme temperature fluctuations. To this end, the researchers led by Dr. Erkan Aydin, group leader at LMU’s Department of Chemistry and Pharmacy, combined two molecular approaches. Their goal was to stabilize both the grain structure within the perovskite material and the interfaces of the solar cells, with a particular focus on enhancing the interaction between the perovskite layer and the underlying substrate. This enables the solar cells to maintain stable performance under the extreme thermal cycling typical of Low Earth orbit (LEO), as well as in other harsh environmental conditions. Their results have been published in the journal Nature Communications.

Regarding the background: Perovskite solar cells are considered one of the most promising next-generation photovoltaic technologies. They are relatively inexpensive to manufacture and achieve high efficiencies.

However, their mechanical stability is an issue. In particular, when confronted with strong temperature fluctuations in LEO—for example, in the range between −80 and +80 degrees Celsius—materials inside the solar cell can expand and contract to varying extents. This creates mechanical stresses, which lead to cracks, delamination, or drops in performance.

Clearest evidence yet that giant planets spin faster than their cosmic lookalikes

For decades, astronomers have struggled to differentiate giant planets from brown dwarfs, a class of objects more massive than planets but too small to ignite nuclear fusion like true stars. Through a telescope, these cosmic lookalikes can have overlapping brightness, temperatures, and even atmospheric fingerprints. The striking similarity leaves astronomers unsure if they have observed an oversized planet or an undersized star. Now, a Northwestern University-led team has uncovered a crucial clue that separates the two: how fast they spin.

In a new study, astrophysicists found the clearest evidence yet that giant planets spin significantly faster than their brown dwarf counterparts. The new results suggest rotation measurements may provide a powerful new diagnostic for classifying these indistinguishable populations and suggest that these two objects evolve differently, perhaps even forming through distinct processes.

The study was published in The Astronomical Journal. It marks the largest survey of spin measurements of directly imaged extrasolar planets and brown dwarfs to date.

How two dim stars came together to shine brightly

Brown dwarfs get a bad rap in the stellar world, often labeled as “failed stars” for their inability to sustain nuclear fusion at their cores. The mass of these objects falls between planets and stars, ranging from 13 to 80 times the mass of Jupiter. Because they aren’t massive enough to sustain fusion, they are far fainter and cooler than their stellar comrades.

Now, a new finding led by researchers at Caltech shows how these dim bulbs can join together to shine brightly. Searching through archival observations captured by the Zwicky Transient Facility (ZTF) at Caltech’s Palomar Observatory, researchers have identified a very tight-knit pair of brown dwarfs in which one is actively siphoning material from the other.

Ultimately, the brown dwarfs are expected to merge to form a new star; alternatively, the brown dwarf gaining the extra mass will ignite to become a star. Either way, a pair of failed stars will have created a brilliant new star.

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