A final flyby for asteroid Bennu and 5 other top space and science stories this week

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Welcome to Wonder Theory, your weekly space and science digest.

In a matter of days, robots achieved milestones across our solar system as researchers here on Earth uncovered windows into the early days of humanity. These contrasting advancements amaze us here at the CNN Space and Science team, especially because they happen so often.

Learning how our ancestors created cave art and engraved prehistoric stone maps transforms these early humans from unrelatable figures to relatives with common ground.

Similarly, the robotic investigators we send to planets and asteroids, those rocky time capsules of the last 4.5 billion years, uncover the past of the solar system. Fueling our curiosity, these insights share not only where we came from, but what had transpired long before humans walked across Earth.

Here are some of the astonishing explorations and discoveries from this week.

Across the universe

The OSIRIS-REx spacecraft has been in an orbital dance with the near-Earth asteroid Bennu since arriving in December 2018 — but that meet and greet is about to come to an end. The spacecraft completed a final flyby of the asteroid on Wednesday, coming as close as 2.1 miles to Bennu’s surface.

The spacecraft is now drifting away from its companion of two-and-a-half years and will depart for Earth on May 10.

Bennu and OSIRIS-REx had a close encounter on October 20, 2020, when the spacecraft briefly touched down on the surface of the asteroid and backed away. This allowed the spacecraft’s sampling arm to collect 2 ounces of material from Bennu that will be returned to Earth in September 2023. The sample could shed more light on the formation of the solar system and how elements like water may have been delivered to early Earth by impacts from asteroids.

The images captured by OSIRIS-REx on its final run will reveal the aftermath of the sample collection event in October, which was a messy affair. Expect to see those images, and how much Bennu’s surface was altered by the rendezvous, next week.

A long time ago…

Ancient cave painters may have purposely sacrificed their ability to breathe in order to create history-making artwork.

New research analyzing cave paintings from 14,000 to 40,000 years ago in Spain and France has shown that many of these works of art can be found in deep, narrow passages of cave systems.

The Upper Paleolithic artists would have needed artificial light to see as they worked. Fire would have diminished the available oxygen, causing hypoxia — releasing dopamine and causing hallucinations, according to the study.

The researchers believe this was a conscious decision that helped the artists connect with the world around them and their beliefs — including the cosmos and the underworld.

The wonder

Another week, another rover selfie on Mars — but this one is even more historic. The Perseverance rover snapped a selfie with the newly independent Ingenuity helicopter, which is sitting in the middle of a Martian air field and preparing for the first powered, controlled flight on another planet.

Until April 3, the helicopter was attached to the belly of the rover since before departing Earth. Since gently dropping on to the surface, the helicopter has been ticking milestones off its list, including surviving freezing nights on Mars and wiggling its blades.

The helicopter is scheduled to have its first flight on Sunday, and the mission control team at NASA’s Jet Propulsion Laboratory will share details from this momentous trial at 11 a.m. ET Monday. If you’re an early bird and want to see the first black-and-white images sent back by the helicopter, tune in to NASA’s mission control at JPL Monday morning beginning at 4:15 a.m. ET.

And then we’ll know how the first Wright brothers moment on another planet transpired. Here’s hoping Ingenuity lives up to its name and has a successful first outing.

Curiosities

A Bronze Age stone map may be the oldest depiction of a territory in Europe, according to new research.

The Saint-Bélec Slab, a partially broken piece of stone covered in engraving, was first discovered in 1900 before it was forgotten for about a century in a museum.

A recent analysis revealed the carvings actually represent 3D depictions of a valley and rivers similar to the landscape of western Brittany in France that “highlights the cartographic knowledge of prehistoric societies,” said Clément Nicolas, a Bournemouth University postdoctoral researcher and first author of the study.

The slab originally was recovered from a burial mound in the same region it depicts and was likely reused in ancient burial to help seal human remains. While the map hasn’t traveled the world, it has served multiple, intriguing purposes.

Climate changed

The arrival of white and pink cherry blossoms, or “sakura,” is often a celebrated sign that spring has arrived in Japan, but this year’s early bloom has scientists worried.

Cherry blossoms are typically associated with April. The flowering trees blossomed early and peaked on March 22 in Tokyo, making it the second-earliest bloom date on record. They bloomed on March 26 in Kyoto — the earliest bloom in the central city in more than 1,200 years.

Warming temperatures around the globe are causing an early end to frosts and the sudden arrival of spring, coaxing the flowers to open earlier, the researchers said. Cherry blossoms in Washington, DC, followed a similar pattern.

This could cause a ripple effect across ecosystems where plants and insects rely on each other for timing and environmental cues and have done so for thousands of years, including valuable crops.

This early bloom is just the tip of the iceberg of a worldwide phenomenon that could destabilize natural systems and countries’ economies, said Amos Tai, associate professor of Earth System Science at The Chinese University of Hong Kong.

Force of nature

Get ready for another wild hurricane season.

Colorado State University shared its forecast for an overactive season Thursday, which includes 17 named storms, eight hurricanes and four major hurricanes (Category 3 or higher). A typical hurricane system usually has 12 named storms, six hurricanes and three major hurricanes.

While the National Oceanic and Atmospheric Administration forecast isn’t due until May, scientists agree that the Atlantic will host a busy hurricane season due to warm ocean surface temperatures and the lack of the calming effects of El Niño, which increases vertical wind shear that prevents hurricanes from forming.

If you live in an area that could be impacted by hurricanes, start preparing now to have an evacuation plan and an updated evacuation kit before the season begins June 1.

Like what you’ve read? Oh, but there’s more. Check back here next Saturday for the next edition of Wonder Theory, brought to you by CNN Space and Science writer Ashley Strickland, who finds wonder in planets beyond our solar system and discoveries from the ancient world.