New galaxy map challenges cosmological models

Credit: Lawrence Berkeley National Lab

MathJax.Hub.Config({tex2jax: {inlineMath: [[‘$’,’$’], [‘\\(‘,’\\)’]]}}); Updated 2 April 2025

The Hubble tension

One experimental anomaly that has bedeviled physicists and cosmologists for years is the discrepancy in values of the Hubble constant based on different experimental approaches. This discrepancy is now known as the Hubble tension.

The Hubble constant $H_0$ is a measure of the rate of expansion of the universe, and is directly connected to estimates of the age $A$ of the universe via the relation $A = 1 / H_0$. Units must be converted here, since the age of the universe is

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Pi Day 2025 crossword puzzle

So soon? Yes, it is that time of year again: Pi Day (March 14, in North American month/date notation) is nearly upon us.

Each year the Math Scholar site celebrates Pi Day with a custom-written crossword puzzle on a mathematical theme. This year’s edition (see below) highlights a memorable comment made by Isaac Newton about his own computation of pi (see puzzle entries 19 Across, 32 Across, 56 Across, 77 Across and 96 Across). However, no particular mathematical knowledge is required to solve the puzzle.

This puzzle is written to the standards of New York Times crossword puzzles (see here),

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