Are there civilizations somewhere else in the universe? Somewhere else in the Milky Way? That's one of our overarching questions, and an answer in the affirmative would be profound.

Humanity has pursued the search for extraterrestrial intelligence (SETI) in one form or another since shortly after the advent of radio waves in the early 20th century. Efforts have waxed and waned over the decades, but the search has never been completely abandoned.

The search detected transient hints in the form of unexplained radio waves in the past, but nothing that comprises reliable evidence.

A new study on nematode worms reveals that physical contact with objects can help prevent neuromuscular decline in simulated microgravity. The research, which was published in the journal iScience, provides new insights into maintaining human health in space.

Over the past 60 years, hundreds of humans have flown into space, sometimes spending up to a year on the International Space Station. Spaceflight subjects the body to near weightlessness or microgravity, which can negatively impact health.

"Progressive neuromuscular decline in microgravity is a major health concern for humans spending time in space," explains Atsushi Higashitani, a molecular biologist at Tohoku University. "Our international team investigated the underlying reasons for these changes."

The researchers studied Caenorhabditis elegans, a nematode worm that shows similar molecular and physiological effects to humans during spaceflight, including impaired muscle performance and reduced body length.

Virgin Galactic, which last year flew its flamboyant founder Richard Branson to space, will re-open ticket sales to the general public starting Wednesday, for the sum of $450,000.

Previously, only people who had paid a deposit to be on a waiting list could buy new tickets—but now sales are once more open to everyone.

"We plan to have our first 1,000 customers on board at the start of commercial service later this year, providing an incredibly strong foundation as we begin regular operations and scale our fleet," said CEO Michael Colglazier in a statement.

Established in 2004, Virgin Galactic is looking to build on the success of a high profile test mission last July, which saw Branson beat Blue Origin founder Jeff Bezos in their billionaire space race by a few days.