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Ancient Rocks in Grand Canyon Reveal Earth's Past Climate and Moon
Confirmed
In Short: Researchers have discovered that the colorful patterns in Hakatai shale in the Grand Canyon preserve a detailed record of Earth's climate and orbit over 1.2 billion years.
These patterns, visible in outcrops 65 kilometers apart, reflect cycles in Earth's climate driven by its movements through space.
The repeating patterns in the shale are geological fingerprints of changes in Earth's climate driven by subtle variations in its orbit and rotation known as Milanković cycles.
By studying these cycles, researchers have reconstructed aspects of the ancient Earth–Moon system.
A lot of variables have to be accounted for, because Earth's orbit is chaotic over very long periods.
Over time, the shape of Earth's orbit changes, its rotational axis changes its tilt, and the orientation of that axis shifts.
The Moon's gradual movement away from Earth has changed the timing of some of these cycles.
Both world powers now appear to favor stability in their relationship, with record Chinese exports and advances in technology.
Former CIA Director John Brennan has been subpoenaed to testify before a Florida grand jury in a Justice Department investigation.
Brennan is also the target of a separate inquiry into whether he made false statements before Congress.
Ken Wainstein, an attorney for Brennan, disclosed the existence of the subpoena as he argued for a court order to preserve all records from the investigations.
What's confirmed
- These patterns, visible in outcrops 65 kilometers apart, reflect cycles in Earth's climate driven by its movements through space.
- The repeating patterns in the shale are geological fingerprints of changes in Earth's climate driven by subtle variations in its orbit and rotation known as Milanković cycles.
- By studying these cycles, researchers have reconstructed aspects of the ancient Earth–Moon system.
- A lot of variables have to be accounted for, because Earth's orbit is chaotic over very long periods.
- Over time, the shape of Earth's orbit changes, its rotational axis changes its tilt, and the orientation of that axis shifts.
- The Moon's gradual movement away from Earth has changed the timing of some of these cycles.
- Both world powers now appear to favor stability in their relationship, with record Chinese exports and advances in technology.
- Former CIA Director John Brennan has been subpoenaed to testify before a Florida grand jury in a Justice Department investigation.
- Brennan is also the target of a separate inquiry into whether he made false statements before Congress.
- Ken Wainstein, an attorney for Brennan, disclosed the existence of the subpoena as he argued for a court order to preserve all records from the investigations.
What's still developing
- This study shows how ancient sediments can preserve far more than a snapshot of the landscape where they formed (in this case, an inland sea).
- CHINESE President Xi Jinping heads into this week’s summit with U.S. President Donald Trump having “outmaneuvered the Trump administration so far,” according to China expert Scott Kennedy of the Center for Strategic and International Studies (CSIS), as the two leaders seek to preserve a fragile commercial truce over tariffs and rare earths.
- He said that could mean China continuing to export rare earths while Washington keeps tariffs from rising, with a possible extension lasting about a year.
- Kennedy said a key test of the summit will be whether Trump and Xi extend the rare-earths and tariff truce and begin a substantive dialogue on artificial intelligence.
- AI, trade and rare earths are all on the agenda, and Kennedy expects commercial issues to dominate the talks, with the two leaders likely to seek an extension of their recent trade ceasefire.
- Xi was expected to depart Washington after touring the nation’s vault of records, where the Declaration of Independence, the constitution and the Bill of Rights are held.
- The two leaders have made a show of working to preserve harmony between the world’s two largest economies, although there were no major breakthroughs on issues such as trade or the safety of artificial intelligence.
- Wainstein said he was told that the subpoena relates to a “far-reaching” criminal probe examining a loosely defined theory that the government officials who have investigated Trump over the last decade, including over Russia election interference in 2016 and his more recent retention of top-secret records at Mar-a-Lago, conspired to deprive Trump of his civil rights.
- Subpoenas demanding testimony before a grand jury in the false statements probe were issued last spring, then abruptly withdrawn in favor of voluntary interviews.
- The subpoena was delivered on the same day that Joe diGenova, the prosecutor who had been leading what is casually known as the “grand conspiracy” investigation, abruptly resigned amid what a person familiar with the matter has described as frustration from the Justice Department and White House over the pace and management of the probe.
- They said the preservation order they sought was especially necessary because of what they described as the Trump administration’s pattern of failing to preserve records.