icy movements
Stonehenge’s central stone, known as the Altar Stone, may be of Scottish rather than Welsh origin, researchers say. The findings suggest that the Late Neolithic group had long-distance connections. bruce bower “Stonehenge’s roots extend to Scotland” (SN: 9/7/24 and 9/21/24, p. 10).
leader Ralph Bradbird I wondered whether glaciers, not humans, could have transported the altar stones, at least in part, from Scotland to southern England, where Stonehenge is located.
This scenario is worth considering, but unlikely, geoscientists say. Anthony Clark Graduated from Curtin University, Perth, Australia. Ice sheet reconstructions show that glaciers moved north from the Grampian Mountains in central Scotland towards the northeastern Orcadia Basin, where the Altar Stone is thought to have originated, he says. Therefore, glacial movements would not have transported the altar stone south to Stonehenge.
Moreover, in southern central England there is little evidence of rocks deposited by glaciers, known as glacial irregularities. clark says In particular, no irregularities in Scotland have been discovered near Stonehenge.
floating in the air
Aerosols that form clouds can be produced during stratospheric air intrusion, when Earth’s jet stream causes stratospheric air to descend into the troposphere below. Carolyn Gramling “Earth’s jet stream seeds clouds” (SN: 9/7/24 & 9/21/24, p. 12).
leader James W. Benefiel We asked whether clouds are more likely to form when water vapor in the upper troposphere condenses into particles.
This is the known mechanism for the formation of cloud condensation nuclei, which are actually tiny particles on which water droplets condense and create clouds. gramling says These particles can form where convective clouds, such as thunderstorm clouds, transport gases or small particles from the Earth’s surface into the atmosphere, where water vapor can condense.
What this new research suggests is a completely different chemical process for cloud formation involving ozone in the stratosphere. gramling says Stratospheric air intrusion events were already a known phenomenon. Now researchers have linked those events to a bump in cloud condensation nucleation. Scientists suggest that the mixing of stratospheric ozone and tropospheric moisture, catalyzed by sunlight, may increase the production of free hydroxyl radicals, which can react with other molecules to produce cloud-forming particles.
Considering the frequency of stratospheric air intrusion events, this mechanism may be an important source of cloud cores. gramling says But how many is not yet known.
Friend or enemy?
Chemical analysis shows that the asteroid that killed the dinosaurs came from beyond Jupiter. Carolyn Gramling “The origin of the dinosaur killer has been revealed” (SN: 9/7/24 and 9/21/24, p. 7).
The story sparked a lively discussion on Reddit about whether Jupiter protects Earth from asteroid and comet impacts.
reddit user Don Manuel Jupiter’s failure to protect Earth from dinosaur killers, he wrote, “shows how important Jupiter’s protection actually is for life on Earth.” But user Astromike23 The idea that Jupiter protects Earth from impacts is a myth, he wrote.
In reality, Jupiter’s role as planetary guardian is not so clear. The planet’s immense gravity could affect the orbits of nearby objects, which could be a double-edged sword for Earth.
Some studies suggest that Jupiter may be able to protect Earth and surrounding planets from impacts by pulling passing asteroids and comets toward itself or hurling them out of the solar system entirely. However, other studies suggest that Jupiter may also launch asteroids and comets into the inner solar system, setting them on a collision course with Earth or its neighbors. Jupiter may also attract objects that wouldn’t normally pass through Earth, increasing the likelihood of collisions.
