A recent study provides the most detailed insight into Earth’s surface temperature fluctuations during the Phanerozoic eon, spanning from 538.8 million years ago to the present. This research reveals that Earth’s temperature has varied more significantly than previously understood and confirms a strong correlation between global temperatures and atmospheric carbon dioxide levels.

The international research team created a comprehensive temperature curve using a method called data assimilation. By analyzing fossil distributions of cold- and heat-tolerant species, along with the chemistry of ancient shells, fossilized microorganisms, and organic matter, scientists were able to reconstruct past ocean temperatures. Additionally, geological indicators such as salt deposits and specific minerals helped map historical climates.

The researchers compiled over 150,000 published data points into a database known as PhanTASTIC (Phanerozoic Technique Averaged Surface Temperature Integrated Curve Project) and integrated this data with modern climate models.

“This method was originally designed for weather forecasting,” says Emily Judd, lead author of the study. “Here, we apply it to hindcast ancient climates rather than predict future weather.”

The team from Arizona collaborated with colleagues at the University of Bristol, generating over 850 climate model simulations based on historical continental positions and atmospheric compositions. By combining these data sources, they constructed a more accurate representation of temperature variations over the last 485 million years.

The findings indicate that global mean surface temperatures ranged from 52 to 97 degrees Fahrenheit (11 to 36 degrees Celsius) during the Phanerozoic. Extreme heat periods were often linked to elevated atmospheric carbon dioxide levels, with solar input playing a lesser role.

Scott Wing, curator of paleobotany at the Smithsonian, notes, “To understand future climate changes, we need to look further back in time to warmer periods, which can provide crucial insights.”

The study reveals that Earth has been significantly cooler in the last 10 to 20 million years compared to the previous 450 million years. However, current anthropogenic climate change is accelerating warming at a rate surpassing even the most rapid warming events of the Phanerozoic.

“Humans and the species we coexist with are adapted to a cooler climate, and rapidly transitioning to a warmer climate poses serious risks,” warns Jessica Tierney, a paleoclimatologist at the University of Arizona. Historical data indicates that episodes of rapid climate change often coincide with mass extinctions.

Although this study represents a significant advancement in our understanding of temperature change, Brian Huber, curator of the micropaleontology collection, emphasizes that it is not the final word. “Researchers will continue to uncover new evidence about the distant past, refining this temperature curve over time.”

The full study, titled “A 485-million-year history of Earth’s surface temperature,” was published in the journal Science. Additional materials and interviews are available from the Smithsonian Institution and the University of Arizona.

There will soon be a new “mini-moon” on Earth, but it won’t last long.

Astronomers predict that the recently discovered asteroid, known as 2024 PT5, will orbit Earth from September 29 to November 25 while momentarily drawn in by our planet’s gravity. After that, the space rock will circle back around the sun in a heliocentric orbit.

This month, the American Astronomical Society’s Research Notes released information on the fleeting mini-moon and the horseshoe-shaped route it takes.

Using the NASA-funded Asteroid Terrestrial-impact Last Alert System, or ATLAS, observatory located in South Africa, astronomers first observed the asteroid on August 7.

Lead study author Carlos de la Fuente Marcos, a researcher at the Complutense University of Madrid’s faculty of mathematical sciences, estimated that the asteroid’s diameter was probably about 37 feet (11 meters), but further observations and data are required to validate its size.

Taken in the afternoon of March 5, 1979, at a distance of 151,800 miles (243,000 kilometers), Voyager 1 captured this image of Ganymede, the biggest satellite of Jupiter.

The space rock may be larger than the asteroid that entered Earth’s atmosphere above Chelyabinsk, Russia, in 2013. Its diameter ranges from 16 to 138 feet (5 to 42 meters). The Chelyabinsk asteroid, which measured between 55 and 65 feet (17 and 20 meters) in size, burst in the atmosphere, producing brightness larger than the sun and 20 to 30 times the energy of the atomic bomb unleashed on Hiroshima, Japan. Over 7,000 buildings were damaged and over 1,000 individuals were hurt by space rock debris.

As a mini-moon, however, asteroid 2024 PT5 poses no threat to Earth right now or in the coming decades, according to de la Fuente Marcos. About ten times the distance between Earth and the moon, or 2.6 million miles (4.2 million kilometers), will separate the space rock’s orbit.

The Process of Creating a Miniature Moon

According to de la Fuente Marcos, there are two kinds of mini-moon phenomena.

Extended occurrences encompass asteroids known as temporarily captured orbiters, which finish one or more full rotations about our planet over the course of one or more years. However, the asteroid doesn’t even make a single full orbit around Earth during brief periods.

According to him, these short-timers, often referred to as momentarily caught flybys, are mini-moons that last a few days, weeks, or months, much like 2024 PT5.

Asteroid 2020 CD3 is one of the temporary mini-moons that Earth has previously acquired. Research revealed that the asteroid had been orbiting our planet for a few years prior to its detection, even though it was first observed whirling about Earth in February 2020 and left a few months later.

The recently discovered asteroid 2024 PT5 is a short-capture mini-moon, but asteroid 2020 CD3 is thought to be a long-capture one.

“In order to become a mini-moon, an incoming body has to approach Earth slowly at close range.”

He said that mini-moon-forming asteroids approach Earth at velocities of less than 2,237 miles per hour (3,600 kilometers per hour) and come within 2.8 million miles (4.5 million kilometers) of the planet.

“Whether an asteroid gets captured by Earth is independent of its size or mass, it only depends on its speed and trajectory as it approaches the Earth-Moon system,” wrote Robert Jedicke, an emeritus specialist on solar system bodies at the University of Hawaii’s Institute for Astronomy, in an email. “Almost all the asteroids that approach Earth do so too fast and at the wrong angle to be captured, but sometimes the combined tugs of all the objects in the solar system contrive to allow a particular (slow) object at the right angle to be briefly captured.”

Jedicke wasn’t part of the most recent research.

2024 PT5 is an asteroid that originated in the Arjuna asteroid belt, a collection of minor asteroids with sun-similar orbits to Earth.

“We think that there is about one dishwasher-size minimoon in the Earth-Moon system at any time, but they are so difficult to detect that most of them go undiscovered during the time that they remain bound to Earth,” Jedicke added. “2024 PT5 might be about 10 meters in diameter, making it the largest captured object discovered to-date.”

Mini-moons could possibly be asteroids from the main asteroid belt, which is situated between Mars and Jupiter, or they could be lunar surface fragments that were propelled millions of years ago by asteroid impacts, according to Jedicke.

He remarked, “Determining where they come from could help us understand the process of crater formation and how material is ejected from the Moon’s surface.”

Next Passovers

Des la Fuente With the Gran Telescopio Canarias and the Two-Meter Twin Telescope, both located on Spain’s Canary Islands, Marcos and his associates intend to view 2024 PT5 in order to gather additional information and details. However, he stated that amateur telescopes or binoculars won’t be able to see the asteroid since it will be too small and dull. There won’t be any noticeable consequences on Earth from it.

The gravitational attraction of the sun will return asteroid 2024 PT5 to its regular orbit after 56.6 days.

The final full-length photo of the asteroid moonlet Dimorphos, captured by NASA’s DART mission’s DRACO imager at a distance of around 7 miles (12 kilometers) and only two seconds before impact. A 100-foot (31-meter)-squared portion of the asteroid is seen in the photograph. The bottom of the picture is where ecliptic north is. This image is mirror flipped across the x-axis from reality and displayed as it appears on the DRACO detector.

However, the analysis predicts that on January 9, 2025, the space rock will swing by Earth closely from a distance of 1.1 million miles (1.7 million kilometers) before “leaving the neighborhood of Earth shortly afterwards, until its next return in 2055.”

Astronomers anticipate that when asteroid 2024 PT5 returns, it will resemble Earth’s mini-moon for a few days in November 2055 and again for a few weeks in early 2084.

Early on Thursday morning, SpaceX accomplished a historic first for a company: its first spacewalk.

Two members of the crew, Jared Isaacman and Sarah Gillis, successfully exited SpaceX’s Dragon capsule “Resilience” during the private Polaris Dawn mission’s grand finale. This is the first spacewalk carried out by private citizens as opposed to government astronauts.

Commander and mission donor Issacman remarked, “Back at home we all have a lot of work to do, but from here, Earth sure looks like a perfect world,”  He declared this after exiting the spacecraft.

SpaceX views the spacewalk—also referred to as extravehicular activity, or EVA—as a critical step in achieving its mission of launching humans into space.

In collaboration with Isaacman, the millionaire inventor of Shift4 payments, SpaceX spent over two years creating space suits that can shield astronauts from the harsh atmosphere of space. Gillis, the mission specialist, and Anna Menon, the medical officer, are the first corporate employees to fly on a mission.

After the spacecraft’s hatch opened, the entire four-person crew was exposed to space vacuum for around two hours during the Polaris Dawn event. For around seven minutes each, Isaacman and Gillis were outside the capsule testing the spacesuits’ maneuverability.

Tuesday saw the mission’s launch by SpaceX. In addition to the spacewalk, Polaris Dawn is conducting approximately 40 science and research experiments, raising money for St. Jude Children’s Research Hospital, and reaching an orbit of more than 1,400 kilometers from Earth, the furthest humans have traveled in space since the Apollo program.

Isaacman, who led the Inspiration4 trip to orbit for the first time in 2021, stated that he is spearheading the Polaris Program to push the envelope of private spaceflight.

“This is the inspiration side of it … anything that’s different than what we’ve seen over the last 20 or 30 years is what gets people excited, thinking: ‘Well, if this is what I’m seeing today, I wonder what tomorrow’s going to look like or a year after,’” Isaacman stated before to the expedition.