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‘Funny dark matter:’ Something is wrong about our theory of the expanding universe
- Our theoretical understanding of the universe predicted a rate of expansion that’s about 8% slower than what we calculated from our actual observations, known as the Hubble tension.
- A new paper published December 9 validates our existing observations by cross-checking the Hubble Space Telescope data with new observations from the James Webb Space Telescope, and finding that the two agree almost perfectly.
- The universe's rate of expansion varies with distance—the further away an object is, the faster it’s moving away from us.
- The rate at which the universe is expanding is expressed as a value called the Hubble Constant, generally abbreviated as “H0”.
- Our best theoretical model for the universe, the Lambda/Cold Dark Matter model (“ΛCDM”), predicts a value for H0 of 67–68 km/s/Mpc.
- The first step is being able to calculate how far away from us distant objects are.
- Once we know how far away an object is, the second piece of information we need is how quickly it’s moving away from us.
- Most of our information on distant objects comes from the Hubble Space Telescope, and James Webb Space Telescope provides a chance to cross-check the data.
- The JWST results correlate almost perfectly with existing data, providing more strong evidence that it’s not the accuracy of our measurements that’s the problem.
- The cosmological constant expresses the intrinsic energy of space itself—the mysterious “dark energy” that current estimates suggest makes up around 68% of the energy in the universe.
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