Each year, astronomers make breathtaking new discoveries that deepen our understanding of the universe and all it contains—and 2024 was no different.
So Newsweek reached out to leading astronomers to share their standout discoveries of the year. Here’s what they had to say.
Wendy Freedman, John & Marion Sullivan University Professor of Astronomy & Astrophysics, The University of Chicago
I found the first results from the Dark Energy Spectroscopic Instrument (DESI) to be exciting. The DESI group has spectra for 6 million (!) galaxies. They looked at how galaxies are distributed as you look back in cosmic time.
Einstein’s theory of gravity predicts what that large-scale distribution of galaxies should be—and it passed the test for how structure grows over time in the universe.
Although it would have been surprising (but interesting!) if Einstein’s general theory of relativity did not hold up, the result rules out alternative theories of gravity, and it tests general relativity on very, very large scales.
And there will be much more to come from this survey as more spectra are obtained in future.
Newsweek Illustration/Canva
George Efstathiou, Leverhulme Trust Emeritus Fellow, Emeritus Professor of Astrophysics, Kavli Institute for Cosmology, University of Cambridge
My favorite results of 2024 are the measurements of the mass fluctuations from the Atacama Cosmology Telescope and from the Dark Energy Spectroscopic Instruments.
They agree really well with the predictions of general relativity. They provide further evidence that the universe is dominated by dark matter and dark energy.
Avi Loeb, Frank B. Baird Jr. Professor of Science, Director, Institute for Theory & Computation, Harvard University
My favorite discovery of 2024 is the Little Red Dots, a class of compact galaxies at early cosmic time discovered by the Webb telescope in March 2024.
Thirty years ago, I published a paper predicting the existence of such galaxies based on the idea that a small fraction of all galaxies will be endowed with a small spin, allowing the gas to settle by self-gravity to a small region where it makes stars and could feed a central supermassive black hole.
The observational discovery paper from 2024 was published here and my explanatory paper from 2024 (referring to my work from 30 years ago) was published here.
Tony Rowell/iStock
Martin Rees, Fellow, Trinity College, and Emeritus Professor of Cosmology and Astrophysics, University of Cambridge; Astronomer Royal
Although this is an obvious choice, I think one has to celebrate the achievements of the James Webb telescope.
Through its sharp angular resolution and ability to observe in the infrared, it has generated real breakthroughs in our conception of newly-forming galaxies.
We understand well how dark matter would clump together as the universe expands, and we would expect the primordial gas to accumulate in the gravitational potential wells provided by these clumps.
The process whereby gas falls in is very complicated we expect it to be more complicated in these early systems because they are denser and the gas can cool more easily, which means that shockwave develop and formation of stars would happen more efficiently.
These galaxies are peculiar shapes because they have not yet settled into equilibrium. (But contrary to the claims of some authors, I don’t think anything in the data invalidates the long-favored ‘cold dark matter’ cosmology: This theory makes definite predictions about the distribution of dark matter, but leaves great uncertainty in the rather messy physics whereby gas agglomerates and converts into stars. But it is wonderful to have such direct images of what the universe was like when it was only about 3 percent of his present age.)
The James Webb telescope has offered an equal boost to what I consider a second equally fascinating growth point in astronomy—namely the properties of the ‘exo-planets’ that are now known to orbit most of the stars in the sky.
In the long run, we hope to be able to get information about the atmosphere and surface structure of planets like the Earth. This is a big challenge but already there is interesting information about so-called ‘water worlds’ which are heavier than the Earth but made of rock rather like Neptune in our own Solar System.
This has stimulated some of the world’s leading microbiologists to focus on the origin of life—an unsolved problem which has been relegated to the ‘too difficult box’ but is now being tackled because of the extra motivation provided by the hope of observing other locations where life could have emerged