Turritopsis dohrnii is now officially known as the only immortal creature. The secret to eternal life, as it turns out, is not just living a really, really long time. It’s all about maturity, or rather, the lack of it. The immortal jellyfish (as it is better known popularly) propagate and then, faced with the normal career path of dying, they opt instead to revert to a sexually immature stage.

It turns out that once the adult form of the 4.5 mm-wide species Turritopsis dohrnii have reproduced, they don’t die but transform themselves back into their juvenile polyp state. Their tentacles retract, their bodies shrink, and they sink to the ocean floor and start the cycle all over again. Among laboratory samples, all the adult Turritopsis observed regularly undergo this change. And not just once: they can do it over and over again.

Thus, the only known way they can die is if they get consumed by another fish or if a disease strikes the jelly. However, there are still many mysteries surrounding the turritopsis dohrnii. While the process of reverting from its adult-phase to a polyp was observed several times, it hasn’t been observed yet in nature, only in laboratory environments.

The nutricula is found in the Caribbean and North America and the cycle reversal was not in fact observed on the nutricula. That doesn’t mean that the nutricula isn’t biologically immortal but that it has not yet been observed and proven that. When the study (Bavestrello et al. 1992; Piraino et al. 1996, 2004) was published, the difference between the dohrnii and nutricula wasn’t clear yet and afterwards the media distributed the information that the nutricula would be the immortal one.

What is Brexit?
Brexit – British exit – refers to the UK leaving the EU.

A public vote (known as a referendum) was held in June 2016, when 17.4 million people opted for Brexit. This gave the Leave side 52%, compared with 48% for Remain. The UK stopped being a member of the European Union (EU) after 23:00 GMT on 31 January 2020.

What is the European Union?
The EU is an economic and political union involving 28 European countries. It allows free trade, which means goods can move between member countries without any checks or extra charges. The EU also allows free movement of people, to live and work in whichever country they choose.
The UK joined in 1973 (when it was known as the European Economic Community) and it will be the first member state to withdraw.

Aside from trade, many other aspects of the future UK-EU relationship will also need to be decided. For example:

Law enforcement, data sharing, and security
Aviation standards and safety
Access to fishing waters
Supplies of electricity and gas
Licensing and regulation of medicines

Prime Minister Boris Johnson insists the transition period will not be extended, but the European Commission has warned that the timetable will be extremely challenging.