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In a major advance in the field of embryology, scientists this week have kept human embryos alive in petri dishes for record amounts of time. The legal limit for keeping fertilised human embryos in the lab is 14 days, a cut-off point set in 1979. Back then, scientists were able to keep embryos alive for only a few days, meaning the limit was only a theoretical one. \\nAdvances mean that this week, in 2 papers, researchers have reached that limit.\\nProfessor Ali Brivanlou, Robert and Harriet Heilbrunn Professor of Stem Cell biology and molecular embryology at Rockefeller University is lead author on one of the papers, and Professor Bobbie Farsides is a clinical and biomedical ethicist at Brighton and Sussex Medical School. They join Adam to discuss the next steps for embryology. Should this limit curtail research?

Next Monday is the transit of Mercury. 13 times a century, Mercury passes directly between us and the Sun, and creates a pinprick shadow, a pixel of black for about 8 hours. This strange planet has no atmosphere, but a lot explosive volcanic activity. It has an eccentric orbit - meaning its distance from the sun fluctuates wildly. A Mercury year is 88 Earth days, but a Mercury day lasts almost two mercury years. \\nDavid Rothery is a professor of Planetary Sciences at the Open University. He reveals how scientists study this planet and explains how, and how not to view the transit of Mercury.

Overfishing is one of the biggest threats to the health of our oceans. According to the UN, up to a third of the world's fisheries are overexploited or depleted. It is a huge complex problem with many inputs and outputs to compute. So who better to tackle it than a team of hackers? Recently, coders around the globe gathered to take on the challenge, in a 48-hour Fishackathon. Reporter Anand Jagatia went along and reports back to Adam

Most dog lovers will know that Labradors are particularly keen to eat anything, all the time, at any time. As a result, some are a bit corpulent, even obese. The cause is likely to be in their genes. A new study in the current issue of Cell Metabolism has identified that genetic basis for the perpetual hunger. Eleanor Raffan from Cambridge University, geneticist and vet, led the study. She explains to Adam how she gathered a cohort of dogs.