Large stars have violent deaths. As they run out of hydrogen to fuse, the star’s weight squeezes its core to make it increasingly hot and dense. The star fuses heavier elements in a last-ditch effort to keep from collapsing. Carbon to Silicon to Iron, each step generating heat and pressure. But soon it’s not enough. The fusion even heavier elements don’t give the star more energy, and the core quickly collapses. The protons and neutrons of nuclei collide so violently that the resulting shock wave rips the star about. The outer layers of the star are thrown outward, becoming a brilliant supernova. For a brief time, the star shines brighter than its entire galaxy, and its core collapses into a neutron star or black hole. It was thought that all large stars end with a supernova, but new research finds that might not be the case.Continue reading “Astronomers Might Have Seen a Star Just Disappear. Turning Straight to a Black Hole Without a Supernova”
The Big Bang produced the Universe’s hydrogen, helium, and a little lithium. Since then, it’s been up to stars (for the most part) to forge the rest of the elements, including the matter that you and I are made of. Stars are the nuclear forges responsible for creating most of the elements. But when it comes to lithium, there’s some uncertainty.
A new study shows where much of the lithium in our Solar System and our galaxy comes from: a type of stellar explosion called classical novae.Continue reading “Much of the Lithium Here on Earth Came from Exploding White Dwarf Stars”
For the child inside all of us space-enthusiasts, there might be nothing better than discovering a new type of explosion. (Except maybe bigger rockets.) And it looks like that’s what’s happened. Three objects discovered separately—one in 2016 and two in 2018—add up to a new type of supernova that astronomers are calling Fast Blue Optical Transients (FBOT).Continue reading “A New Kind of Supernova Explosion has been Discovered: Fast Blue Optical Transients”
The biggest stars in our universe are some of the most fascinatingly complex objects to inhabit the cosmos. Indeed,giant stars have defied full explanation for decades. Especially when they’re near the end of their lives.
Stars power themselves through nuclear fusion, from the smashing together of lighter elements into heavier ones. This process leaves behind a little bit of extra energy. It’s not much, but when those fusion reactions occur at millions or billions of times every single second, it’s enough to keep a star powered for…millions or billions of years.Continue reading “Take a Peek Inside a Giant Star Right Before it Dies”
Since 1958, the NASA Explorer Program has conducted low-cost missions that were deemed relevant to the goals of the Science Mission Directorate (SMD), particularly where the study of our Sun and the deeper cosmic mysteries are concerned. Recently, the Explorer Program selected four missions that they considered to be well-suited to these goals, two of which will be selected for launch in the coming years.
Consisting of two astrophysics Small Explorer (SMEX) and two Missions of Opportunity (MO) proposals, these missions are designed to study cosmic explosions and the debris they leave behind, as well as monitor how nearby stellar flares may affect the atmospheres of orbiting planets. After detailed evaluations, two of these missions will be selected next year and will take to space sometime in 2025.Continue reading “NASA Chooses 4 New Astronomy Space Missions for Additional Study”
Astronomers have a dark energy problem. On the one hand, we’ve known for years that the universe is not just expanding, but accelerating. There seems to be a dark energy that drives cosmic expansion. On the other hand, when we measure cosmic expansion in different ways we get values that don’t quite agree. Some methods cluster around a higher value for dark energy, while other methods cluster around a lower one. On the gripping hand, something will need to give if we are to solve this mystery.Continue reading “The Chemicals That Make Up Exploding Stars Could Help Explain Away Dark Energy”
It’s no secret that planet Earth is occasionally greeted by rocks from space that either explode in our atmosphere or impact on the surface. In addition, our planet regularly experiences meteor showers whenever its orbit causes it to pass through clouds of debris in the Solar System. However, it has also been determined that Earth is regularly bombarded by objects that are small enough to go unnoticed – about 1 mm or so in size.
According to a new study by Harvard astronomers Amir Siraj and Prof. Abraham Loeb, it is possible that Earth’s atmosphere is bombarded by larger meteors – 1 mm to 10 cm (0.04 to 4 inches) – that are extremely fast. These meteors, they argue, could be the result of nearby supernovae that cause particles to be accelerated to sub-relativistic or even relativistic speeds – several thousand times the speed of sound to a fraction of the speed of light.Continue reading “There Could be Meteors Traveling at a Fraction of the Speed of Light When They Hit the Atmosphere”
The universe is expanding. When we look in all directions, we see distant galaxies speeding away from us, their light redshifted due to cosmic expansion. This has been known since 1929 when Edwin Hubble calcuated the relation between a galaxy’s distance and its redshift. Then in the late 1990s, two studies of distant supernovae found that the expansion of the universe is accelerating. Something, some dark energy, must be driving cosmic expansion.Continue reading “New Research Casts A Shadow On The Existence Of Dark Energy”
Astronomers at Cardiff University have done something nobody else has been able to do. A team, led by Dr. Phil Cigan from Cardiff University’s School of Physics and Astronomy, has found the neutron star remnant from the famous supernova SN 1987A. Their evidence ends a 30 year search for the object.Continue reading “Astronomers Finally Find the Neutron Star Leftover from Supernova 1987A”
Japanese astronomers have captured images of an astonishing 1800 supernovae. 58 of these supernovae are the scientifically-important Type 1a supernovae located 8 billion light years away. Type 1a supernovae are known as ‘standard candles’ in astronomy.Continue reading “Subaru Telescope Sees 1800 Supernovae”