Light-light
A quick one
from particle physics before we plunge in the skies. The Atlas and CMS experiments at the Large Hadron Collider published news about a kind of event expected but never seen before.
The collisions in the heart of the accelerator a hundred meters underground are a real jungle, as subatomic particles get created, bump into each other, disappear and give place to new ones in the blink of a blink. And within these collisions lurks the reflection of light off light, as the experiments confirmed.
It is to be noted that this "light-light scattering" supposedly cannot happen according to the theory of electromagnetism, which otherwise can describe pretty much everything happening around us. It was only after the concept of particles and the theories describing their physics that this luminous bumping was predicted - and confirmed seventy years later.
Life on moon
Remember how we were lamenting about lunar programs being abandoned for so long, with only China dealing with two moon landings in the last dozen of years?
And now?
Now, within just a few days there is an Indian craft approaching the moon and... well... a crash with probably the most original consequences of any lunar mission ever: installing life on the moon.
The Israeli craft Beresheet would have carried the first ever lunar expedition on private funding and the fourth country ever on the moon (also the first country among those encouraging women to cover their head, but I digress). Only that it lost control and crashed just seconds before landing. However, its cargo included an artifact carrying memorabilia from earth and designed to endure for millions of years. It contains nano-etchings of extensive terrestrial bibliography (and the guide to decoding it), a few human DNA samples, and thousands of hibernated animals of the most badass species on earth.
The most badass species on earth is the tardigrade, millimeter-long tactopoda discovered only years ago in Antarctica although they live literally anywhere on the planet. They have a baffling and weirdly cute appearance, they can withstand the most extreme conditions and they can enter a state of indefinitely long suspension; biologists have revived them from a thirty-year-long suspension but for all we know it could last millions of years; which matches the lifetime of their protective case on the moon.
After the crash calculations showed that the artifact has most probably survived it. In that case the tardigrade astronauts are staying dormant, but they just became the strongest ambassadors of humanity into the future, whatever this might mean.
Galactic action
Meanwhile, the Keck observatory in Hawaii was announcing that a few months ago the supermassive black hole at the centre of the Milky Way shone exceptionally brightly for a few days (actually, they took a look again after the announcement and it still does)! Its brightness was the highest in twenty years of observations and 75 times stronger than its average.
This light comes from the material falling into the hole as it heats up due to friction and its change probably means that something large came close… The main candidate is S0-2, the star closest to and actually orbiting the black hole: last year its orbit brought them within a distance of just 16 light-hours; not to say that it was swallowed (it wasn’t), but it may have fed the hole some extra material.
What next? Now that this shine is noticed, complementary observations from different telescopes are expected to clarify this small mystery for us in the near future.
Exotic gravity
The LIGO and Virgo interferometers, responsible for bringing us gravitational waves, have been at it again. Among their latest sightings of celestial bodies too heavy to be imagined spiralling around and falling into each other, they caught a new one: the merging of a neutron star and a black hole.
(Neutron stars and black holes have each been captured merging in pairs before but it's the first time they show up together. How do the interferometer people know that it's them, you say? By checking the signal against various simulated scenarios and seeing which one it matches better.)
A comet and its moon
Is a cute name all it takes to include a piece of news in a newsletter? Well, maybe it is : |
Spacecraft Rosetta’s celebrated mission to comet 67P/Churyumov-Gerasimenko that ended in 2016 left behind a wealth of pictures. As an astrophotographer was going through that stack of old photos, he realized that the comet has its own tiny moon. Which is actually a 4-meter chunk of ice, propelled away from the comet in 2015 due to the sun’s heat, but captured by its gravity in an orbit of 3 kilometers.
In a brilliant move, the chunk of ice was named Churymoon by a PhD student and the name was immediately adopted by the European Space Agency, resulting in it making headlines all over the world. I shared this with you because I didn’t want to be the only one doing stuff around the house and randomly saying aloud “Churymoon!.. Churymoon!..”
