In very important news, a bunch of microscopic, virtually indestructible creatures known as tardigrades (or water bears, depending on who you ask) may or may not have survived a crash landing on the Moon.

If you didn't already know, tardigrades are eight-legged micro-animals that are found pretty much anywhere, from mountains to Antarctica.

The little creatures are famed for their hardiness, with scientists reporting their ability to withstand heat extremes and starvation — among other things.

That's all well and good, you say, but why were water bears sent to the Moon?

The Beresheet lander took a picture of the Moon before it crash landed with tardigrades aboard. ( Reuters: Space IL )

How did tardigrades get on the Moon?

Israeli company Arch Mission foundation sent a probe by the name of Beresheet up to the Moon in April.

Had it made it, it would've been the first private lander to touch down there.

Except, as we know, it did not. Mission controllers lost contact as the lander was making its way down and it unceremoniously crashed on the surface.

But before it did, the company packed the probe with earthly things to act as a backup of our dear planet, and to "preserve the records of our civilisation for up to billions of years", Nova Spivack, the man behind the Arch Mission Foundation, told Wired.

Arch Mission Foundation's lander would have been the first private lander on the Moon. ( Reuters: Space IL )

The library comprised a nickel disk, which contained copies of classic books, human blood samples, nearly all of the Wikipedia articles available in English and, you guessed it, tardigrades.

Or, tardigrades coated in a protective resin, at least.

"Tardigrades are ideal to include because they are microscopic, multicellular, and one of the most durable forms of life on planet Earth," Mr Spivack told Wired of the decision to include them.

So that's why they were sent to the Moon. But are they likely to have survived the crash landing?

'The Moon's pretty safe from a tardigrade invasion'

Mr Spivack told Wired: "In the best-case scenario, Beresheet ejected the Arch Mission Foundation's lunar library during impact and it lies in one piece somewhere near the crash site."

The entrepreneur said he was basing this estimation on an analysis of the Beresheet's trajectory and the composition of the device the water bears were stored in.

But what do the experts say?

According to Mark Siddall, curator of invertebrates at the American Museum of Natural History in New York City and of travelling exhibition Nature's Superheroes: Life at the Limits, the chances of the tardigrades having survived are slim.

He explained to the ABC that the tardigrades sent to the Moon would have been put into a "tun" phase, a state that sees them pull their legs in and secrete an outer cellular layer around their body as protection, before being coated in resin.

"This is a stage that lacks water and is not a state of living per se," Dr Siddall said.

"The longest known suspended tun state for a tardigrade that was brought back to an animated, hydrated form is about 10 years.

"Of the tardigrades that were exposed to the vacuum of space and its radiation for only 12 days, only 12 per cent survived being rehydrated, and then they suffered rapid mortality after being rehydrated.

"Neither of these includes a high-energy crash. The probability of survival after months of exposure to galactic and solar radiation and a vacuum after a high energy impact I would put at 'vanishingly small'."

One expert said tardigrades exposed to UV radiation in controls had all died. ( Supplied: Wikimedia commons )

Paul Bartels, a professor of biology at Warren Wilson College who specialises in the microscopic beasts, agreed, putting the chance of tardigrade survival in this case at almost zero.

And he said, anyone saying otherwise was "totally divorced from actual experimental results".

"[Some articles have said tardigrades] are the only animals to survive exposure to space. Then they have gone on to speculate they could colonise space.

"Colourful, if true, but actual space flight experiments [conducted so far have] not exposed them to [every aspect of] space," he added.

Dr Bartels said experiments conducted with tardigrades in space saw them transported in temperature-controlled compartments that were shielded from UV radiation.

He said this was significant because tardigrade samples exposed to UV radiation in controls had all died.

"I don't doubt the animals could have survived the temperature of space, but we don't have any evidence to support that other than super cold temperatures they've been exposed to here on Earth," he said.

"But the clincher is they [have] all died from UV exposure. The Moon has no atmosphere to speak of, so UV-B and UV-C would be deadly unless somehow they found a little cosy UV-free nook somewhere.

"So, as much as I worry about invasive exotics, I think the Moon's pretty safe from a tardigrade invasion," Dr Bartels added.

What makes the idea of tardigrades on the Moon exciting?

So, the experts say it's likely the water bears didn't survive their Moon landing this time around.

Why did the world make such a fuss about the possibility that they had?

Dr Bartels said the possibility of tardigrades on the Moon would be exciting "in a good way and in a scary way" for the world of science.

"If they could do this, it would suggest that space travel and colonisation is possible by Earth organisms and by extension life could travel and may already have travelled to and from Earth," he said.

The scary part of this, Dr Bartels said, is that the survival of tardigrades on the Moon "would suggest that humans could take our exceptional skills at destroying Earth ecosystems through the introduction of invasive exotics on the road, so to speak. This is a very real concern."

Dr Suzie Reichman said the ability of tardigrades to survive out there would tell us a lot about the possibilities for life in the universe. ( Reuters: Space IL )

RMIT associate professor Suzie Reichman specialises in the study of soil pollution, which is how she came to work with tardigrades.

She told the ABC the ability of tardigrades to survive on the Moon would tell us a lot about the possibilities for life on our planet and in the universe.

"If there are organisms from our planet that are able to survive on the Moon, it opens up the possibility of us potentially in the future being able to have colonies [there].

"That's why it captures peoples' imagination," she said.

What would it take to kill a tardigrade?

The answer to this may disappoint some.

Dr Reichman told the ABC tardigrades only become the hardy creatures they're known as when in their tun state.

"They can die, just like any other soil organism, when they're not in their tun state. They're not any more tolerant than any other organisms.

To exist outside their tun state, they need oxygen and water, Dr Reichman said. And as we already know, they can't withstand UV radiation.

They can also be squished very easily, according to Dr Bartels.