Tidal disruption events, in which supermassive black holes rip stars apart, could supercharge ghostly subatomic particles called neutrinos, emily conover reported in “Zippy neutrino linked to a source” (SN: 6/18/22, pg. 8).
Conover reported that scientists traced a high-energy neutrino to an area of the sky where a bright flare, thought to be a tidal disruption event, had been discovered about a year earlier. Reader Doug McElroy he wanted to know if the neutrino observation delay reveals the distance of the tidal disruption event from Earth.
it doesn’t, Conover He says. “High-energy neutrinos and light travel at about the same speed (neutrinos are a bit slower due to their mass), so the difference in travel time shouldn’t make much of a difference when we look at the particles.” , He says.
Instead, the timing suggests that the process of a black hole ripping apart a star, creating an environment that accelerates particles, may take a while. Conover He says. In this case, at least one year. Scientists believe that this particular neutrino would have been emitted about a year after the flare from the tidal disruption event.
dust it off
Biological soil crusts — thin layers of soil glued together by land-dwelling organisms — reduce global dust emissions by about 60 percent, Nikk Ogasa reported in “Biocrusts keep dust settled” (SN: 6/18/22, pg. 12).
Additional dust could affect river flows, ogasa wrote. For example, falling dust in the upper Colorado River basin reduced meltwater flows in the Colorado River by an average of about 5 percent each year. Reader greg skala he asked how dust can have such an effect on runoff.
Dust that fell on the basin’s snowy surfaces decreased the amount of sunlight they reflected, causing the snow to melt several weeks earlier than anticipated. ogasa He says. That left the vegetation and soils that were buried underneath exposed for a longer period, increasing the amount of water lost to the air through a process called evapotranspiration. As more water was lost to the air, less eventually reached the river.
Scientists observed two black holes merging into one. Gravitational waves then pushed the newly formed black hole away from home, emily conover reported in “Space waves gave the boot to the black hole” (SN: 6/18/22, pg. 8).
Reader bradley ruben he wondered if the discovery implies that there are lone, rogue black holes zipping through space, potentially destroying solar systems or other celestial objects along the way.
Isolated black holes that travel through space exist, Conover He says. In fact, scientists may have seen one a few thousand light years from Earth (SN: 7/16/22 and 7/30/22, pg. eleven). But the implications are not as dramatic as one might imagine.
Space is really big, and the number of lone black holes is relatively small, which makes direct black hole hits very rare. Conover He says.
“And contrary to popular belief, black holes don’t ‘suck in’ everything around them,” he says. If the black hole doesn’t get too close and just passes by, it would simply exert a gravitational pull on the planetary system it encounters. In that way, it would act similar to any other massive object traveling through space, like a star, she says.