Author: BBC World Service

It’s citrus season in the northern hemisphere, and fruit trees are bursting with oranges and lemons. But CrowdScience listener Jonathan wants to know what happened to the tangerines he ate as a child in the 1960s? He remembers a fruit that was juicy, sweet and full of pips, found each Christmas at the bottom of his stocking. Tangerines today, he thinks, just don't compare.

Crowdscience tries to track down this elusive fruit. Presenter Anand Jagatia traces the tangerine's origins back to Ancient China, as botanist David Mabberley explains that the name ‘tangerine’ comes from a fruit that made its way from Asia, to Africa and the Moroccan port of Tangier, before arriving in the US in the early 1800s. Professor Tracy Kahn from UC Riverside tells us about the hybridisation process that goes into breeding modern tangerines, but says that while the season for these fruits has been dramatically extended, there’s a cost in terms of diversity and flavour.

Who better to help us track down this missing mandarin than a fruit detective? Well, that’s one of pomologist David Karp’s other job titles, and he reveals exactly which cultivar we might be looking for: the Dancy. So where can we find one? Over on Friend’s Ranches in Ojai, California, Emily Ayala shows us two trees planted by her late grandfather, and explains that nothing grown since really matches its unique flavour.

So what will listener Jonathan think when we send him a box?

Presenter: Anand Jagatia Producer: Marijke Peters Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Jackie Margerum

(Image: Citrus oranges grow on tree, Hong Kong Credit: CHUNYIP WONG via Getty Images)

Unexpected Elements has a shake up looking into the topsy turvy world of science, all thanks to an upturned campervan in Western France.

Explore why scientists are suspending rhinos from cranes, brace yourself for a quirky elementary particle that is hard to get your head around and if you love getting yourself in a tizz then fasten your seatbelts to meet one of the scientists responsible for curating the perfect theme park thrills. Professor Brendan Walker is sure to inject a scientific rush that will make you question who you take on your next roller coaster ride.

Crack open the World Service archives to delve into the curious world of cryonics, exploring the science behind preserving bodies in suspended animation.

And, have you wondered what your favourite music genre says about you? We uncover the surprising psychology behind your musical tastes.

Presenters: Caroline Steele, with Andrada Fiscutean and Phillys Mwatee. Producers: Harrison Lewis, with William Hornbrook, Debbie Kilbride and Noa Dowling

Just two weeks ago the world learned of an asteroid that had an almost 3% chance of striking earth in less than a decade. Astronomers kept looking, and a team including Olivier Hainaut at ESO’s Very Large Telescope at Palanar, in Chile, have managed to narrow down the uncertainty such that we now know it will definitely not hit the earth. The secret of making such observations after most telescopes could no longer see it was down to the exceptionally dark skies there.

But these may be under threat. A plan has been made to build a large power plant, including sustainable hydrogen production around 11km away from the otherwise isolated site, and astronomers around the world are rallying to call for the plant to be built further away so that its construction will not spoil the otherwise unique observation conditions.

One of the signatories of a petition to that effect is Julia Siedel, also of ESO, who just last week published the first 3D atmospheric analysis of an exoplanet’s climate. As she explains, future similar observations using the forthcoming, co-sited Extremely Large Telescope could be thwarted before the telescope is even finished.

Back on earth, the Atlantic Meridional Overturning Current (AMOC) continues to bring warmer air and nutrients north towards the Arctic, and colder, denser water south in the global ocean overturn. But are reports of its collapse under climate change justified? A new paper this week suggests that for the next century at least it is stable though it might slow down. Jonathan Baker of the UK Met office explains how the winds in the south mean the cycle will keep turning, though it may slow down.

Talking of the Arctic, Yoel Fink of MIT has dressed a couple of royal marines in wearable computer fibres for their current icy patrol in the north of Canada. Far from going commando, their underwear is measuring temperature and calorific burn to help them avoid frostbite and the dangers of the extreme environment. Yoel’s paper this week describes the new device and the principle that in the future much of all of our healthcare will be provided by these sorts of wearable, stretchy, computing textiles monitoring our activities.

Presenter: Roland Pease Producer: Alex Mansfield Production co-ordinator: Jana Bennett-Holesworth and Josie Hardy

(Photo: Celestial conjunction at Paranal. Credit: Y.Beletsky/ESO)