Dr. Brian Welch joins ISSI to investigate the origins of elements in young galaxies and unravel the mysteries of galaxy formation and evolution in the early universe.
Webinar with Mike Wong (University of California, USA)
Thursday, 25th September 2025
(17h CEST | 11h EDT)
Please click here for the Zoom Session
Meeting ID: 852 6990 9362 Password: 459004
The Outer Planet Atmospheres Legacy (OPAL) program with Hubble was started in 2014 with the goal of studying time-domain phenomena in Jupiter, Uranus, and Neptune, with Saturn added in 2018 once the Cassini spacecraft was de-orbited. Key areas of study are heat transport and climate circulation, atmospheric structure and evolution, composition, the formation of clouds and hazes, impact processes, and impactor populations.
Apart from inconceivable amounts of dark energy and dark matter, the rest of our universe—only around 4 %—is filled with normal matter, so called baryons. Surprisingly, only a small fraction of that normal matter can be observed through starlight emitted by galaxies.
The Hubble Space Telescope has been called the most productive scientific instrument in human history. Launched in 1990, the telescope has performed observations which have measured the age of the Universe, confirmed the existence of black holes, discovered the accelerating Universe, and amazed the general public. On Christmas day in 2021 the James Webb Space Telescope (JWST) was launched into space after decades of development. JWST was designed to extend the view of Hubble in regions of the cosmos Hubble can’t penetrate. JWST is exceeding the grand expectations of its ability to unravel the mysteries of the Universe. Join Astronaut/Astrophysicist John Grunsfeld as he takes us through the stories of Hubble and Webb.
In this last year, the Pantheon+ and SH0ES teams released likely our last measurements of the expansion history of the universe. On one hand, constraints from Pantheon+ show a universe consistent with the Lambda-CDM model, where dark energy can be described by a cosmological constant. On the other hand, constraints combining Pantheon+SHOES data find a high value of the Hubble constant, now 5sigma away from the value inferred using Lambda-CDM from measurements of the Cosmic Microwave Background. How can both these statements be true? In this talk, the speaker goes over these separate but overlapping measurements, and discussess how we can have tensions with some parts of the cosmological model but not others. The speaker discusses possible explanations to the Hubble tension, and goes over how other tensions have arisen in cosmology. Finally, the speaker talks about how new telescopes, like the James Webb Space Telescope, can help resolve these controversies.
