Darren wants to know, 'Why can we see the light from the first galaxies. Why hasn't that light already passed us if it is from so long ago when the universe was smaller.' Strap in for a mind bending journey across the universe with James Tytko and Daniel Whiteson, Professor of Physics and Astronomy at the University of California, Irvine. Be sure to check out Daniel's podcast: 'Daniel and Kelly's Extraordinary Universe.' Like this podcast? Please help us by supporting the Naked Scientists

Joao wants to know what happens when stem cells of our own, which have been cultivated outside the body, are reintroduced to the bloodstream. This got James Tytko thinking about autologous stem cell transplants, used as a treatment for some forms of blood cancer. He asked Tania Dexter, haematology registrar, and senior medical officer at the Anthony Nolan Institute, to help explain... Like this podcast? Please help us by supporting the Naked Scientists

Will wants to know what the implications would be for our world if the landmass was rotated 90 degrees, so current day Mexico was nearer the South Pole. Trying to wrap his head round all of the possible implications, James Tytko enlisted Dr Alex Farnsworth, Senior Research Associate from the School of Geographical Sciences at the University of Bristol, to help come up with an answer... Like this podcast? Please help us by supporting the Naked Scientists

Brian wants to know, if 2 AI's were to have a conversation with one another, what would they talk about? James Tytko put this query to the test, and asked Mike Pound, professor of computer vision at the University of Nottingham, to help make sense of it all... Like this podcast? Please help us by supporting the Naked Scientists

Thanks to John Maher for the answer! Like this podcast? Please help us by supporting the Naked Scientists

Kiran wants to know how animals like dogs are able to follow commands from humans. James Tytko asked Nicky Clayton, Professor of Comparative Cognition at the University of Cambridge, to help with the answer... Like this podcast? Please help us by supporting the Naked Scientists

Alan writes in, acknowledging that many animals use the Earth's magnetic field for navigation purposes. Given the shifts in poles and field intensity we experience due to convection currents in the Earth's core, how do they stay on course? James Tytko asked Miriam Liedvogel, professor of ornithology, to help find the answer... James - The best supported ideas include the presence of a tiny compass needle of magnetic iron oxide in the beaks of some birds. Or there's the radical pair hypothesis, which explains magnetoreception with quantum mechanics. Mirjam Liedvogel is director of the Institute... Like this podcast? Please help us by supporting the Naked Scientists

In 1977, astronomer Jerry Ehman detected a narrowband radio signal, far stronger than any that have been recorded before or since, using Ohio State University's Big Ear telescope as it was pointing in the direction of the Saggitarius constellation. Listener to the show, Donald, wants to know if any consensus has been reached as to the origin of the signal, which James Tytko sought to find out with the help of former BBC science editor, David Whitehouse. Like this podcast? Please help us by supporting the Naked Scientists

Thanks to John Travers for the answer!Listener Francisco asked: I have been told that jumping on a trampoline is healthy for humans. It is considered as a good exercise; and also to better coordinate brain and body. I am 73 and wonder whether it is advisable for me to jump on a spring board?John - My work in reversing frailty and building resilience in older adults has made me a big advocate for resistance exercises like trampolining. This should be combined with consuming sufficient protein to turn that work into stronger muscles and bones. Jumping on a trampoline can improve cardiovascular... Like this podcast? Please help us by supporting the Naked Scientists

Silke is writing all the way from French Polynesia, asking what's best to do with all the plastic rubbish she picks up from the beach, and whether burning it is advisable. James Tytko asked Richard Lampitt from the National Oceanography Centre to help find an answer... Like this podcast? Please help us by supporting the Naked Scientists