A round-up of today's other science stories in brief
Artificial jellyfish constructed in US
IS IT A jellyfish? Is it a rat? Or how about a bit of both. Researchers in the US have constructed an artificial "jellyfish" using cells from rat heart muscle grown on a polymer structure.
The curious result, which is described this week in Nature Biotechnology, propels itself along. And, if you were to meet it swimming, from a distance you could be forgiven for thinking you had encountered the real thing.
To make the construct, the team at Harvard University and Caltech took their cues from looking at how jellyfish propel themselves. They then grew rat heart muscle cells on a flower-shaped, eight-armed polymer substrate. Next, they put the construct into a container of salty water and applied an electrical current. The rat cells contracted and the jellyfish-shaped structure started to be propelled along.
Researcher Prof Kevin Kit Parker from Harvard School of Engineering and Applied Sciences explains where he got the inspiration to come up with such a thing.
“[It came from] a visit to the New England Aquarium on a day when I was particularly disappointed with heart research and looking for something to build. I saw it, said I can build this and off we went,” he says. “I knew it would take the form of a cell monolayer and polymer membrane as soon as I saw it.”
Parker describes how he thought the jellyfish construct was “beautiful” when he saw it swim for the first time, and adds that they have been inspired to create artificial constructs based on more creatures – others are already in the queue.
A spiral galaxy far, far away
SOMETIMES WHEN you look out into the vastness of space, something surprising can catch your attention. Last week, astronomers in Canada and the US reported in Nature what they reckon is the earliest seen spiral galaxy, BX442, observed as it existed roughly three billion years after the Big Bang.
Why is this noteworthy? For one thing, you don’t expect such ancient galaxies to have such well-defined spiral arms.
“BX442 is one of those cases in science akin to ‘bumble bees can’t fly – but they do’,” explains astrophysicist Dr Niall Smith from Blackrock Castle Observatory and Cork Institute of Technology, who was not involved in the study. “The current theories of galaxy formation posit that the early universe was a very energetic place with lots of random motion of gas that couldn’t easily be tamed by gravity. Thus we expect, and generally find, that early galaxies are misshapen and generally irregular.”
They haven’t had enough time for gravity to bring them into some of the spectacular, but somehow regular or ordered, shapes we see in galaxies such as our own Milky Way, he adds. So what does BX422’s spiral shape mean?
“The discovery of BX442 suggests that the establishment of order took place much earlier than previously predicted, and it’s exciting because it challenges the general theoretical view,” says Smith. “As in the case of the bumble bee, this is an example where observational science is essential. Although it’s possible to generate a self-consistent model for a universe. Without observations there are no ways to put constraints on the models.”