Out of this world control on Ice Age cycles
2023-05-15
(Press-News.org)
A research team, composed of climatologists and an astronomer, have used an improved computer model to reproduce the cycle of ice ages (glacial periods) 1.6 to 1.2 million years ago. The results show that the glacial cycle was driven primarily by astronomical forces in quite a different way than it works in the modern age. These results will help us to better understand the past, present, and future of ice sheets and the Earth’s climate.
Earth’s orbit around the Sun and its spin axis orientation change slowly over time, due to the pull of gravity from the Sun, the Moon, and other planets. These astronomical forces affect the environment on Earth due to changes in the distribution of sunlight and the contrast between the seasons. In particular, ice sheets are sensitive to these external forces resulting in a cycle between glacial and interglacial periods.
The present-day glacial-interglacial cycle has a period of about 100,000 years. However, the glacial cycle in the early Pleistocene (about 800,000 years ago) switched more rapidly, with a cycle of about 40,000 years. It has been believed that astronomical external forces are responsible for this change, but the details of the mechanism have not been understood. In recent years, it has become possible to investigate in more detail the role of astronomical forces through the refinement of geological data and the development of theoretical research.
A team led by Yasuto Watanabe at the University of Tokyo focused on the early Pleistocene Epoch from 1.6 to 1.2 million years ago using an improved climate computer model. Astronomical forces based on modern state-of-the-art theory are considered in these simulations. The large numerical simulations in this study reproduce well the glacial cycle of 40,000-year of the early Pleistocene as indicated by the geological record data.
From analysis of these simulation results, the team has identified three facts about the mechanisms by which astronomical forces caused changes in climate in those times. (1) The glacial cycle is determined by small differences in the amplitude of variation of the spin axis orientation and the orbit of the Earth. (2) The timing of deglaciation is determined mainly by the position of the summer solstice on its orbit, which is at perihelion, not only by the effect of periodical change of the tilt of the Earth’s axis. (3) The timing of the change in the spin axis orientation and the position of the summer solstice on its orbit determines the duration of the interglacial period.
“As geological evidence from older times comes to light, it is becoming clear that the Earth had a different climatic regime than it does today. We must have a different understanding of the role of astronomical forcing in the distant past,” says Takashi Ito from the National Astronomical Observatory of Japan, a member of this research team who led the discussion on astronomical external forces. “The numerical simulations performed in this study not only reproduce the Pleistocene glacial-interglacial cycle well, but also successfully explain the complex effects of how astronomical forcing drove the cycle at that time. We can regard this work as a starting point for the study of glacial cycles beyond the present day Earth.”
These results appeared as Watanabe Y. et al. “Astronomical forcing shaped the timing of early
Pleistocene glacial cycles” in Communications Earth & Environment on May 15, 2023.
END
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2023-05-15
In the medicine market, most newly introduced drugs and drug candidates show poor water solubility, which prevents their absorption in the body. This, in turn, limits their therapeutic efficiency. Solubilizing agents such as cyclodextrins (CDs) are commonly employed to enhance their solubility. CDs have a cyclic structure featuring a hydrophilic exterior and a hydrophobic cavity inside that can enclose drug molecules to form inclusion complexes. However, solubilization does not necessarily enhance drug adsorption in the body, since the solubilized drugs cannot ...
2023-05-15
Ithaca, NY (May 15, 2023) - Today, the Boyce Thompson Institute (BTI) is taking a significant step forward in its mission to bridge the gap between scientific discovery and real-world application. Thanks to a generous $1M gift from the Cane-Bridge Foundation, BTI has launched an innovative translational program called "Project Vault!" to propel plant science discoveries into applications that tackle global life science challenges.
"The Cane-Bridge Foundation's support is vital to accelerate ...
2023-05-15
SAN ANTONIO — May 15, 2023 —Southwest Research Institute (SwRI) scientists observed the first close-ups of a source of energetic particles expelled from the Sun, viewing them from just half an astronomical unit (AU), or about 46.5 million miles. The high-resolution images of the solar event were provided by ESA’s Solar Orbiter, a Sun-observing satellite launched in 2020.
“In 2022, the Solar Orbiter detected six recurrent energetic ion injections. Particles emanated along the jets, a signature of magnetic reconnection involving ...
2023-05-15
Older buildings tend to leak heat through their walls, requiring much more energy to maintain a comfortable temperature in summer or winter. Those constructed prior to the late 1970s rarely meet today’s more rigorous energy standards. And yet they account for large proportion of the buildings standing today. In the US, about 44% of the residential building stock was built before 1970 and about half of the commercial buildings that exist today were built before the 1980s, which creates a significant need for energy retrofitting to reduce environmental impact. A new industry-academic collaboration between Jefferson and Lightweight ...
2023-05-15
Asbestos materials were once widely used in homes, buildings, automobile brakes and many other built materials due to their strength and resistance to heat and fire, as well as to their low electrical conductivity. Unfortunately, asbestos exposure through inhalation of small fiber particles has been shown to be highly carcinogenic.
Now, for the first time, researchers from the University of Pennsylvania have shown that extremophilic bacteria from high temperature marine environments can be used to reduce asbestos’ toxicity. The research is published in ...
2023-05-15
WHAT:
A first-in-human clinical trial of an experimental oral drug for removing radioactive contaminants from inside the body has begun. The trial is testing the safety, tolerability and processing in the body of escalating doses of the investigational drug product HOPO 14-1 in healthy adults. The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, is funding the Phase 1 trial, which is sponsored and conducted by SRI International of Menlo Park, California.
Internal radioactive contamination occurs when radioactive ...
2023-05-15
Clam leases are designated underwater locations used to produce hard clams of all sizes from littlenecks to chowders. Clam production or aquaculture can be a risky business due in part to unwanted marine intruders. Among them, stealthy and highly mobile rays.
The Indian River Lagoon is one key location used for hard clam (Mercenaria mercenaria) aquaculture operations along Florida’s Atlantic coast. Clam fishermen have anecdotally reported seeing rays in clam leases and suspect that their interactions could result in damaged aquaculture gear and crushed clams. After all, ...
2023-05-15
CAPE COD, MASSACHUSETTS – Earlier this year, the US Environmental Protection Agency proposed maximum allowable levels in drinking water for six PFAS (per- and polyfluoroalkyl substances) – so-called forever chemicals. But the draft standards do not account for half of the PFAS at contaminated sites across the country.
The findings are from a team led by the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and are published in the journal Environmental Science & Technology.
PFAS are present in fire retardant foams ...
2023-05-15
Embargoed for release: Monday, May 15, 2023, 8:00 AM ET
Boston, MA – People who live in communities with higher proportions of Black and Hispanic/Latino residents are more likely to be exposed to harmful levels of per- and polyfluoroalkyl substances (PFAS) in their water supplies than people living in other communities, according to a new study led by researchers from Harvard T.H. Chan School of Public Health. The researchers link this finding to the disproportionate siting of sources of PFAS pollution—such ...
2023-05-15
WINSTON-SALEM, NC – MAY 15, 2023 – The Wake Forest Institute for Regenerative Medicine (WFIRM) will make history this month when the first bioprinted solid tissue constructs soar to the International Space Station (ISS) on board the next all private astronaut mission by commercial space leader Axiom Space.
The Axiom Mission 2 (Ax-2) launch by Houston-based Axiom Space is launching from Florida’s Kennedy Space Center. The crew will conduct extensive scientific research experiments including WFIRM’s vascularized tissue research – which won first place in the NASA Vascular Tissue Challenge in 2021.
Liver ...
LAST 30 PRESS RELEASES:
[Press-News.org] Out of this world control on Ice Age cycles