Space can be an unfriendly place for the human body, with microgravity conditions and other factors tampering with our physiology, from head to toe – head, of course, being a primary concern.

A new NASA-funded study provides a deeper understanding of the issue. Researchers said on Thursday that astronauts who traveled on the International Space Station (ISS) or NASA space shuttles on missions lasting at least six months experienced significant expansion of the cerebral ventricles – spaces in the middle of the brain containing cerebrospinal fluid, Reuters reported.

This colorless and watery fluid flows in and around the brain and spinal cord. It cushions the brain to help protect against sudden impact and removes waste products.

Based on brain scans of 30 astronauts, the researchers found that it took three years for the ventricles to fully recover after such journeys, suggesting that an interval of at least that duration would be advisable between longer space missions.

“If the ventricles don’t have sufficient time to recover between back-to-back missions, this may impact the brain’s ability to cope with fluid shifts in microgravity. For example, if the ventricles are already enlarged from a previous mission, they may be less compliant and/or have less space to expand and accommodate fluid shifts during the next mission,” said University of Florida neuroscientist Heather McGregor, lead author of the study published in the journal Scientific Reports.

Age-related ventricular enlargement – caused not by microgravity but by brain atrophy – can be associated with cognitive decline.

“The impact of ventricular expansion in space travelers is not currently known. More long-term health follow-up is needed. This ventricular expansion likely compresses the surrounding brain tissue,” University of Florida applied physiology and kinesiology professor and study senior author Rachael Seidler said.

The absence of Earth’s gravity modifies the brain.

“This seems to be a mechanical effect,” Seidler said. “On Earth, our vascular systems have valves that prevent all of our fluids from pooling at our feet due to gravity. In microgravity, the opposite occurs – fluids shift toward the head. This headward fluid shift likely results in ventricular expansion, and the brain sits higher within the skull.”

The study involved 23 male and seven female astronauts – average age around 47 – from the U.S., Canadian and European space agencies. Eight traveled on space shuttle missions of about two weeks. Eighteen were on ISS missions of about six months and four on ISS missions of about a year.

Little to no ventricular volume change occurred in astronauts after short missions. Enlargement occurred in astronauts after missions of six months or longer, though there was no difference in those who flew for six months compared to those who did so for a year.

“This suggests that the majority of ventricle enlargement happens during the first six months in space, then begins to taper off around the one-year mark,” McGregor said.

The fact that enlargement did not worsen after six months could be good news for future Mars missions on which astronauts may spend two years in microgravity during the journey.

“This preliminary finding is promising for astronaut brain health during long-duration missions, but it’s still important that we examine MRI data from a larger group of astronauts and following even longer missions,” McGregor said.

The absence of enlargement following short flights was good news for people who may consider short space tourism jaunts, Seidler added, as that industry develops.

Microgravity conditions also cause other physiological effects due to the reduced physical load on the human body. These include bone and muscle atrophy, cardiovascular changes, issues with the balance system in the inner ear and a syndrome involving the eyes. Elevated cancer risk from the greater exposure to solar radiation that astronauts may encounter the further they travel from Earth is another concern.

Google is building AI into its products faster than most with Gmail becoming the latest Google app to get an injection of artificial intelligence, to improve search results on mobile.

“When searching in Gmail, machine learning models will use the search term, most recent emails and other relevant factors to show you the results that best match your search query,” Google explains in a blog post.

“These results will now appear at the top of the list in a dedicated section, followed by all results sorted by recency,” the post continues. In other words, AI will (in theory) pick out the best matches for your search, and put them at the top of the list, Tech Radar reports.

This is coming to the Gmail apps for Android and iOS, and should be rolling out for everyone now. As yet, there’s no word on whether or not the same feature will be making an appearance in the desktop web interface for Gmail.

AI has been built into Gmail for years of course, with features like Smart Reply composing short automated replies for you but in recent months, Google has been pushing more advanced, generative AI as a way of composing your emails.

More AI features are heading to search on the web too, while development on the ChatGPT rival Google Bard continues at a steady pace.

Scientists have expanded the search for technologically advanced extraterrestrial civilizations by monitoring a star-dense region toward the core of our galaxy for a type of signal that could be produced by potential intelligent aliens that until now has been ignored.

Efforts to detect alien technological signatures previously have focused on a narrowband radio signal type concentrated in a limited frequency range or on single unusual transmissions. 

The new initiative, scientists said this week, focuses on a different signal type that perhaps could enable advanced civilizations to communicate across the vast distances of interstellar space, Reuters reported.

These wideband pulsating signals for which the scientists are monitoring feature repetitive patterns – a series of pulses repeating every 11 to 100 seconds and spread across a few kilohertz, similar to pulses used in radar transmission. The search involves a frequency range covering a bit less than a tenth the width of an average FM radio station.

“The signals searched in our work would belong to the category of deliberate ‘we are here’ type beacons from alien worlds,” said Akshay Suresh, a Cornell University graduate student in astronomy and lead author of a scientific paper published in the Astronomical Journal describing the new effort.

“Aliens may possibly use such beacons for galaxy-wide communications, for which the core of the Milky Way is ideally placed. One may imagine aliens using such transmissions at the speed of light to communicate key events, such as preparations for interstellar migration before the explosive death of a massive star,” Suresh added.

The effort, called the Breakthrough Listen Investigation for Periodic Spectral Signals (BLIPSS), is a collaboration between Cornell, the SETI Institute research organization and Breakthrough Listen, a $100 million initiative to search for advanced extraterrestrial life.

Using a ground-based radio telescope in West Virginia, BLIPSS has focused upon a sliver of the sky less than one-200th of the area covered by the moon, stretching toward the center of the Milky Way roughly 27,000 light years away. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).

This area contains about 8 million stars, Suresh said. If extraterrestrial life forms exist, they presumably would populate rocky planets orbiting in what is called the habitable zone, or Goldilocks zone, around a star – not too hot and not too cold.

The scientists in the various monitoring efforts passively scan for signals of alien beings and do not actively send their own signals advertising our presence on Earth.

No aliens yet have been detected in the monitoring efforts.