Author: BBC World Service

It’s the central question for the current generation of Mars missions. Since the first close-up pictures of the red planet back in 1965, decades of space missions have revealed our neighbouring planet to be cold, rocky and sterile. But there are hints of a more dramatic past; of raging volcanoes and flash floods. Could this be a planet where life existed? Could life still exist under the surface? And could humans live there, or even travel the distance to get there safely, at some point in the coming decades?

CrowdScience listeners from Australia, Ghana and Canada have been musing on all sorts of Martian matters. Presenter Marnie Chesterton visits a corner of Stevenage, UK, with a distinctly unearthly appearance and takes a virtual tour of the Martian atmosphere. She also puts listeners’ questions to the scientists designing the spacecraft and instruments they hope will unlock the secrets of Mars.

(Image: illustration of Mars shot from space. Credit: Getty Images)

The idea of creating underwater habitats has captured the imagination of writers, thinkers and scientists for decades. However, despite numerous grand visions, these dreams of aquatic metropolises have not yet come to fruition. Crowdscience listener and scuba enthusiast Jack wonders whether - given improved technology and the growing environmental pressures facing humans on land - it is time to reconsider the ocean as an alternative permanent living space for humans.

Marnie Chesterton dons her flippers for Crowdscience in search of the oceanographers and architects who have dedicated their lives to designing vessels, labs and underwater habitats. She explores whether oceanic cities remain a sci-fi dream or a realistic solution to some of our modern challenges. Can the oceans’ largely unexplored resources be harnessed to support living underwater?

(Photo: Illustration of a modern city under the sea. Credit: Getty Images)

What is light and can we trap it in a box? On this edition of CrowdScience, Marnie Chesterton brings you a kaleidoscope of colourful questions from listeners around the world, from Kampala to Chicago. Shireen asks why people have a favourite colour and whether other animals show colour preferences too. Marnie heads to the zoo to see what the birds, bees and butterflies think. There, she meets a colour-changing chameleon to find out how and why it does because of a question from Dramadri in Uganda.

Meanwhile, Paul in Melbourne is interested to know more about colour blindness. And finally, Feroze asks why we only see a portion of the electromagnetic spectrum and wants to know if we might, one day, hack our vision to see beyond the seven colours of the rainbow.

Presenter: Marnie Chesterton Producer: Graihagh Jackson

(Photo: Stardust and magic in a woman hands on a dark background. Credit: Getty Images)

Hedgehogs are the UK’s favourite British mammal. They have cute furry faces, a snuffly nose and the ability to gobble up garden slugs. What’s not to like? Answer: quite a lot if you live in the Outer Hebrides. Hedgehogs were introduced to South Uist in the 1970s as garden pest controllers, but are now serious pests in their own right – munching their way through the eggs and chicks of globally important wading bird populations. This emblem of cuteness is really a killer. So what’s to be done?

That’s the quandary facing this week’s CrowdScience thanks to a question from Juan Carlos in Cuba. He wants to know how different parts of the world are dealing with invasive species – one of the biggest threats to global biodiversity. Presenter Anand Jagatia heads to the Uists to hear how having an invader that’s loved by millions can cause a whole host of problems. He also discovers how various warring parties eventually came together to solve this very prickly problem.

Also in the programme, Anand travels to South Africa to find out how researchers are coping with invasive trees by introducing another non-native species. While in the Caribbean, we hear how people are dealing with invasive fish by eating them.

Presenter: Anand Jagatia Producer: Anna Lacey

(Photo: A European hedgehog. Credit: Getty Images)

Teenagers are known for ignoring their parents’ advice, but is this reputation for rebellion well-founded? If so, is rejecting the advice of previous generations and treading our own path an important part of what it means to be human? Are we successful as a species precisely because of our questioning natures? Listener Hans started pondering these questions after his own adolescent children repeatedly ignored his nagging. Many animals simply follow in their parents’ footsteps – so what makes human children different?

Marnie Chesterton and a panel of experts look at the science of taking advice and making decisions, finding out how human curiosity and exploration compare to other animals, learning the best ways to give and take advice, and seeing whether we’re more likely to trust artificial intelligence than the wisdom of our elders. Finally, we give listener Hans some expert advice on whether or not to keep nagging his kids.

Presenter: Marnie Chesterton Producer: Cathy Edwards

(Image: A father and son having communication issues. Credit: Getty Images)