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Science & Discovery
Saturn's rings exist because of a mathematical boundary. Anything inside it cannot hold itself together.
The Roche limit is the distance at which a planet's tidal forces overcome a satellite's self-gravity, preventing it from accreting or tearing it apart. Saturn's rings sit inside this boundary for water ice, which is why they exist as rings rather than as one large moon.
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Science & Discovery
Every atom heavier than hydrogen was forged inside a star. Here is how that happened.
Stellar nucleosynthesis is the process by which stars manufacture every element from helium to iron in their cores, and supernovae and neutron star mergers produce everything heavier. The atoms in your body have a detailed provenance that astrophysicists have largely worked out.
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Science & Discovery
In the first fraction of a second after the Big Bang, the universe grew by a factor of 10 to the 26th power. Here's what we know about that.
Cosmic inflation — a period of exponential expansion in the universe's first 10^-32 seconds — was proposed in 1980 to solve three problems with the standard Big Bang model. Evidence for it is strong; direct detection of its signature in gravitational waves remains the goal.
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Science & Discovery
Frank Drake wrote seven terms on a blackboard in 1961. Here's what we know about each of them now.
The Drake Equation estimates the number of communicating civilizations in the galaxy from seven factors. In 1961, most were guesses. In 2026, exoplanet surveys, astrobiology, and SETI experiments have turned several of them into data. The answer is still unknown — but for different reasons than before.
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Commercial
Some things can only be made in zero gravity. A small industry is building the infrastructure to make them.
Microgravity enables manufacturing processes impossible on Earth: near-perfect optical fibers, protein crystals for drug development, organs grown without scaffolding, and alloys that separate under gravity. A nascent commercial sector is building the satellites and ISS platforms to exploit these properties.
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Commercial
SpaceX has launched more than 6,000 satellites. Astronomers are not happy about it.
Starlink is the largest satellite constellation in history — and the most disruptive to ground-based astronomy. SpaceX has made mitigation efforts, but the fundamental tension between dense LEO constellations and telescope surveys remains unresolved as competitors plan their own systems.
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Commercial
SpaceX cut the cost of reaching orbit by 90 percent. Here's what that has and hasn't changed.
The cost of putting a kilogram in low Earth orbit dropped from roughly $50,000-$70,000 in the Space Shuttle era to under $3,000 on a Falcon 9 rideshare. This 90-percent price reduction has transformed who can access space — but it hasn't yet transformed what they do there.
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Science & Discovery
Solar panels stop working past Jupiter. Nuclear reactors are the only practical power source for deep space.
Radioisotope thermoelectric generators have powered deep-space probes since the 1960s. A new generation of compact fission reactors — Kilopower and its successors — could power permanent lunar bases, Mars surface missions, and spacecraft to the outer planets and beyond.
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Missions
Artemis is more than a Moon landing. It's a permanent outpost architecture. Here's the full picture.
Artemis is NASA's plan for sustained human presence near the Moon: a Gateway station in lunar orbit, commercial landers for surface access, the Lunar Terrain Vehicle, and a base camp at the south pole. The architecture is ambitious, politically contingent, and unlike anything attempted in the Apollo era.
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Stargazing
Five planets are visible without a telescope. Here's when and where to find each of them in 2026.
Mercury, Venus, Mars, Jupiter, and Saturn are all visible to the naked eye under dark skies. Their positions shift throughout the year as Earth and the planets orbit the Sun. This guide covers the best viewing windows and what to look for in 2026.
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Science & Discovery
JWST can sniff exoplanet atmospheres. Scientists are debating what a 'biosignature' actually proves.
Biosignatures — atmospheric chemicals whose presence is difficult to explain without biology — are the primary observational strategy for detecting life on exoplanets. JWST has made the first detections of molecules in rocky exoplanet atmospheres. The challenge is interpreting them unambiguously.
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Stargazing
Light pollution has erased the Milky Way for a third of humanity. Dark sky preserves are the counterweight.
The Bortle scale measures sky darkness from 1 (pristine dark) to 9 (inner city). A third of Earth's population lives under skies so bright they cannot see the Milky Way at all. Dark sky preserves — certified by the International Dark-Sky Association — are growing, but so is the light encroachment they resist.
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