The journal · The real sky
Deep sky and cosmology
Black holes, galaxies and the expanding universe. What's established and what isn't.
8 articles.
The Andromeda collision: what happens in 4 billion years
Two galaxies merging, and essentially zero chance of any two stars hitting each other.
2 min read
The Big Bang: evidence, not just theory
Four independent lines of evidence, one confirmed by accident, and one very common misunderstanding.
4 min read
Black holes: what we know
Imaged, detected in gravitational waves, and still hiding the interesting part. Less mysterious than the documentaries want.
4 min read
Dark matter and dark energy for non-physicists
Unrelated, despite the names. One is real and unfound. The other is a label for an observation.
4 min read
The first image of a black hole: how they did it
A telescope the size of the planet, and data too big to send over the internet.
2 min read
Galaxy types: spiral, elliptical, irregular
Three main shapes, and a classification diagram whose arrow points the wrong way.
4 min read
How far can we see? The observable universe explained
13.8 billion years old, 46 billion light years across. Both are correct.
4 min read
Redshift and the expanding universe
Light stretched by expanding space. Not a Doppler shift, whatever the textbooks say.
2 min read
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