Lifeboat Foundation

The end of the universe as we know it will not come with a bang. Most stars will slowly fizzle as their temperatures fade to zero.

“It will be a bit of a sad, lonely, cold place,” said theoretical physicist Matt Caplan, who added no one will be around to witness this long farewell happening in the far far future. Most believe all will be dark as the universe comes to an end. “It’s known as ‘heat death,’ where the universe will be mostly black holes and burned-out stars,” said Caplan, who imagined a slightly different picture when he calculated how some of these dead stars might change over the eons.

Punctuating the darkness could be silent fireworks—explosions of the remnants of stars that were never supposed to explode. New theoretical work by Caplan, an assistant professor of physics at Illinois State University, finds that many white dwarfs may explode in supernova in the distant far future, long after everything else in the universe has died and gone quiet.

Observations of dwarf galaxies around the Milky Way have yielded simultaneous constraints on three popular theories of dark matter.

A team of scientists led by cosmologists from the Department of Energy’s SLAC and Fermi national accelerator laboratories has placed some of the tightest constraints yet on the nature of dark matter, drawing on a collection of several dozen small, faint satellite galaxies orbiting the Milky Way to determine what kinds of dark matter could have led to the population of galaxies we see today.

The new study is significant not just for how tightly it can constrain dark matter, but also for what it can constrain, said Risa Wechsler, director of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at SLAC and Stanford University. “One of the things that I think is really exciting is that we are actually able to start probing three of the most popular theories of dark matter, all at the same time,” she said.

Hubble Finds That Betelgeuse’s Mysterious Dimming Is Due to a Traumatic Outburst

Observations by NASA ’s Hubble Space Telescope are showing that the unexpected dimming of the supergiant star Betelgeuse was most likely caused by an immense amount of hot material ejected into space, forming a dust cloud that blocked starlight coming from Betelgeuse’s surface.

Hubble researchers suggest that the dust cloud formed when superhot plasma unleashed from an upwelling of a large convection cell on the star’s surface passed through the hot atmosphere to the colder outer layers, where it cooled and formed dust grains. The resulting dust cloud blocked light from about a quarter of the star’s surface, beginning in late 2019. By April 2020, the star returned to normal brightness.

Betelgeuse has been the center of significant media attention lately. The red supergiant is nearing the end of its life, and when a star over 10 times the mass of the Sun dies, it goes out in spectacular fashion. With its brightness recently dipping to the lowest point in the last hundred years, many space enthusiasts are excited that Betelgeuse may soon go supernova, exploding in a dazzling display that could be visible even in daylight.

While the famous star in Orion’s shoulder will likely meet its demise within the next million years — practically couple days in cosmic time — scientists maintain that its dimming is due to the star pulsating. The phenomenon is relatively common among red supergiants, and Betelgeuse has been known for decades to be in this group.

Coincidentally, researchers at UC Santa Barbara have already made predictions about the brightness of the supernova that would result when a pulsating star like Betelgeuse explodes.

S4714 can reach the unfathomable speed of nearly 15,000 miles per second.

In 1987, astronomers witnessed a spectacular event when they spotted a titanic supernova 168,000 light-years away in the Hydra constellation. Designated 1987A (since it was the first supernova detected that year), the explosion was one of the brightest supernova seen from Earth in more than 400 years. The last time was Kepler’s Supernova, which was visible to Earth-bound observers back in 1604 (hence the designation SN 1604).

Since then, astronomers have tried in vain to find the company object they believed to be at the heart of the nebula that resulted from the explosion. Thanks to recent observations and a follow-up study by two international teams of astronomers, new evidence has been provided that support the theory that there is a neutron star at the heart of SN 1604 – which would make it the youngest neutron star known to date.

The studies that describe their respective findings were both published in The Astrophysical Journal. The first, “High Angular Resolution ALMA Images of Dust and Molecules in the SN 1987A Ejecta,” appeared in the November 19th, 2019, issue while the second, “NS 1987A in SN 1987A,” was published in the July 30th, 2020 issue. Both studies represent the culmination of thirty years of research and waiting by astronomers.

Astronomers have long suspected a city-sized neutron star hides within the dusty shroud of SN 1987A. And now, they’re closer than ever to proving their case.

But the extraordinary sight of a nearby supernova lingering in Earth’s night sky isn’t the only thing SN 1987A bestowed upon us. It also gave astronomers an unprecedented opportunity to investigate what triggers supernovae, as well as how such powerful blasts ripple through their surroundings. In fact, we can see the shockwave from SN 1987A still speeding outward today, interacting with clouds of dust that encircle the original site of the cosmic explosion.

Detailed computer simulations have found that a cosmic contraction can generate features of the universe that we observe today.

We investigate a suspected very massive star in one of the most metal-poor dwarf galaxies, PHL 293B. Excitingly, we find the sudden disappearance of the stellar signatures from our 2019 spectra, in particular the broad H lines with P Cygni profiles that have been associated with a massive luminous blue variable (LBV) star. Such features are absent from our spectra obtained in 2019 with the Echelle Spectrograph for Rocky Exoplanet- and Stable Spectroscopic Observation and X-shooter instruments of the European Southern Observatory’s Very Large Telescope. We compute radiative transfer models using cmfgen, which fit the observed spectrum of the LBV and are consistent with ground-based and archival Hubble Space Telescope photometry. Our models show that during 2001–2011, the LBV had a luminosity L_* = 2.5–3.5 × 10⁶ L_⊙, a mass-loss rate ˙ M = 0.005 − 0.020 M ⊙ yr⁻¹, a wind velocity of 1000 km s⁻¹, and effective and stellar temperatures of T_eff = 6000–6800 and T_* = 9500–15 000 K. These stellar properties indicate an eruptive state. We consider two main hypotheses for the absence of the broad emission components from the spectra obtained since 2011. One possibility is that we are seeing the end of an LBV eruption of a surviving star, with a mild drop in luminosity, a shift to hotter effective temperatures, and some dust obscuration. Alternatively, the LBV could have collapsed to a massive black hole without the production of a bright supernova.