When the Large Hadron Collider was first about to be turned on, some people fretted (needlessly, as I pointed out in "LHC and FUD") that its operation might produce black holes, or stranglets, or whatever, to devour the Earth. The gist of my counterargument (and that of others) was that there exist cosmic rays with higher energy than anything the LHC can produce. (The LHC collides particles with combined energies of a paltry few trillion electron volts, tera-eV. Cosmic rays sometimes have energies up to a quadrillion electron volts, peta-eV.) If billions of years of cosmic rays smacking into Earth's atmosphere hasn't done in the planet, nothing the LHC can do is going to hurt us.
|Cosmic rays and cascading showers|
From the recent determination of the source of these ultra-high-powered charged particles -- the galactic core -- it seems likely that the super-massive black hole in that vicinity is involved. Without yet knowing the exact mechanism of cosmic-ray acceleration, it makes intuitive sense that something as powerful as a super-massive black hole is involved. See "Astronomers find source of most powerful cosmic rays."
Meanwhile, at the galactic outskirts ...
Do things enter the Milky Way from outside? Yup. In fact, there is a "Gigantic Gas Cloud on Collision Course With Our Galaxy." That cloud has an estimated mass equal to a million suns -- but spread across an enormous volume. My opinion: there's no need for thoughts of the impending collision to keep you up nights. Not unless you object to a bit of new-star construction (apt to result from shock waves induced in that tenuous cloud by the coming collision). And unless you'll be around in, say, 30 million years.
|Large Magellanic Cloud|
And from, well, we don't know where, but far (an estimated 1.3 billion light-years) away, something gave rise to the first gravitational waves astronomers have ever detected. Analysis indicates that the waves originated in the merger of two black holes. Yowza. For a straight-up report on the finding, see "Gravitational waves, Einstein's ripples in spacetime, spotted for first time." For a peek ahead to what the nascent field of gravitational-wave astronomy might mean, see "Gravitational Waves: 6 Cosmic Questions They Can Tackle." And for all the naysayers who said a career in science will never pay, see "Scientists win $3 million for detecting Einstein's waves."
And that's as far afield as this blogger intends to get today. Till next time ...