“Colliding neutron stars in Stockholm? What does that even mean?” you might wonder as you stand before the Gravitational Ripples. It is not about the city’s infrastructure but rather about the cosmos. Gravitational Ripples represents a groundbreaking area of scientific exploration.
Let’s dive into the depths of space. Imagine two neutron stars locked in a cosmic dance. These stars are the ultra-dense collapsed cores of exploded stars. They weigh as much as our sun but are only about 20 kilometers across. The gravity on their surface is two hundred billion times stronger than on Earth.
These binary neutron stars are orbiting each other. They spiral inward, generating gravitational waves. These waves ripple outwards into space. Eventually, the stars crash into each other. This forms a single neutron star. In many cases, this new star will soon collapse into a black hole.
This collision is not silent. It produces vast amounts of heavy radioactive matter. This matter is expelled into space. The collision becomes visible as a burst of electromagnetic radiation. Scientists call this event a kilonova or macronova.
Here in Stockholm, researchers are deeply involved in studying these kilonova events. The Gravity Meets Light project at Stockholm University connects experts from various departments. They cover the entire kilonova event. This includes modeling the beginning of the spiral, the merger and nucleosynthesis, and the light curve and spectral appearance. The project aims to determine how these exotic transients can be used for cosmology.
Scientists like Stephan Rosswog and Anders Jerkstrand lead this research. They hope to answer fundamental questions. These include how the heaviest elements are formed and how fast the universe is expanding. Other notable members include Jesper Sollerman, Hiranya Peiris, and Ariel Marcelo Goobar.
In June 2024, Stockholm hosted a symposium on gravitational wave science. World leaders in the field presented the current status and outlook of this new window on the Universe. The detection of gravitational waves from merging black holes and neutron stars has already led to revolutionary scientific breakthroughs. It even resulted in the 2017 Nobel Prize in Physics.
The symposium aimed to foster the development of gravitational wave science in Sweden. Early career scientists from all Swedish universities were particularly welcome. Experts like Patrick Brady, Alessandra Bounanno, and Samaya Nissanke shared their insights. Researchers from Stockholm University, such as Nikhil Sarin and Evan O’Connor, also contributed.
Gravitational Ripples is a reminder of the profound research happening here. It shows how scientists in Stockholm are helping us understand the universe. They are unraveling the mysteries of neutron stars and gravitational waves. As you stand here, consider the immense forces at play in the cosmos and the brilliant minds dedicated to understanding them.