Icy strikes
Stonehenge’s central stone, referred to as the Altar Stone, might have had Scottish and never Welsh origins, researchers say. The discovering means that Late Neolithic teams had long-distance connections, Bruce Bower reported in “Stonehenge’s roots lengthen to Scotland” (SN: 9/7/24 & 9/21/24, p. 10).
Reader Ralph Bradburd questioned if a glacier, not people, might have not less than partly transported the Altar Stone from Scotland to southern England, the place Stonehenge is situated.
That state of affairs is value contemplating however is unlikely, says geoscientist Anthony Clarke of Curtin College in Perth, Australia. Ice sheet reconstructions present that glaciers moved northward from the Grampian Mountains in central Scotland towards the Orcadian Basin within the northeast, the place the Altar Stone is assumed to have come from, he says. So glacial motion up there wouldn’t have introduced the Altar Stone south to Stonehenge.
What’s extra, there may be little proof of rocks deposited by glaciers, referred to as glacial erratics, in central southern Britain, Clarke says. And particularly, erratics from Scotland haven’t been discovered close to Stonehenge.
Up within the air
Cloud-forming aerosols could also be solid throughout stratospheric air intrusion occasions, through which Earth’s jet streams trigger stratospheric air to dip into the underlying troposphere, Carolyn Gramling reported in “Earth’s jet streams sow cloud seeds” (SN: 9/7/24 & 9/21/24, p. 12).
Reader James W. Benefiel requested whether or not it’s extra seemingly for clouds to kind when water vapor within the higher troposphere condenses on particles.
That is really a identified mechanism for the formation of cloud condensation nuclei, the tiny particles that water droplets condense onto and that are the genesis of clouds, Gramling says. Such particles can kind the place convective clouds, comparable to thunderstorm clouds, carry gases or tiny particles from Earth’s floor excessive into the environment, the place water vapor can condense onto them.
What this new research suggests is a completely completely different chemical course of for cloud formation, which entails ozone from the stratosphere, Gramling says. Stratospheric air intrusion occasions had been already a identified phenomenon. Now researchers have linked such occasions to a bump within the formation of cloud condensation nuclei. The scientists suggest that the blending of stratospheric ozone with tropospheric moisture, catalyzed by daylight, might enhance the manufacturing of free hydroxyl radicals, which may react with different molecules to create the cloud-forming particles.
Given the frequency of stratospheric air intrusion occasions, this mechanism could also be a major supply of cloud nuclei, Gramling says. However simply how a lot remains to be unknown.
Pal or foe?
A chemical evaluation means that the asteroid that killed the dinosaurs got here from past Jupiter, Carolyn Gramling reported in “Dinosaur killer’s origin revealed” (SN: 9/7/24 & 9/21/24, p. 7).
The story sparked a full of life dialogue on Reddit about whether or not Jupiter shields Earth from asteroid and comet collisions.
Reddit person DonManuel wrote that Jupiter’s failure to guard Earth from the dino-killer exhibits “how essential the safety of Jupiter actually is for all times on Earth.” However person Astromike23 wrote that the concept that Jupiter shields Earth from impacts is a fantasy.
Certainly, Jupiter’s function as a planetary protector will not be so clear-cut. The planet’s immense gravitational pull can affect the orbits of close by objects, which could possibly be a double-edged sword for Earth.
Some research counsel Jupiter might defend Earth and neighboring planets from impacts by pulling passing asteroids and comets towards itself or flinging them out of the photo voltaic system completely. However different analysis suggests Jupiter may also slingshot asteroids and comets into the internal photo voltaic system and arrange a collision course with Earth or its neighbors. Jupiter might even appeal to objects that wouldn’t usually go Earth, growing the probability for collision.
