a new insight into one of the mysteries of the natural world, how butterflies fly despite being equipped with large, inefficient wings. they ve discovered that butterflies cup their wings when taking off. this forms an air pocket that pushes the insect forward at speed, helping it to escape predators. researchers believe the knowledge could prove useful in other spheres, such as making some drones and underwater vehicles more efficient. this is bbc world news, the latest headlines: joe biden and kamala harris lead a ceremony to honour the 400,000 americans who ve died during the pandemic. president trump releases a farewell video on his last day in office before issuing his presidential pardons, including one for key former aide steve bannon. netflix got a big boost from the pandemic last year, as demand for streaming movies and television soared. the company now has more than 200 million paid members, up more than 30% from 2019. about 37 million people subscribed last year, including
have a label, is the case for the atrocities being committed against the uighur people in china by the communist party. stay with us on bbc news, still to come: the puzzle of how butterflies fly has been solved and the answer could propel human travel. donald trump is now the 45th president of the united states. he was sworn in before several hundred thousand people on the steps of capitol hill in washington. it s going to be only america first. america first. demonstrators waiting for mike gatting and his rebel cricket team were attacked with tear gas and set upon by police dogs. anti apartheid campaigners say they will carry on the protests throughout the tour.
what the snp want, though, is it? i mean, they voted for a no deal brexit so under their plans, it would have been even harder. and as the music industry themselves have said, what they need now is clarity, not recriminations. and that, mr speaker, is what the british government are working to provide. the culture secretary will be hosting a roundtable discussion with musicians on this matter. i do not know if the six pistols have been invited. and, thank you very much. a new study has helped solve the puzzle of how butterflies take to the air. for decades, scientists thought their large wings were aerodynamically inefficient. but they ve now worked out that butterflies cup their wings when taking off, forming an air pocket that pushes the insect forward helping it to escape predators. laura foster reports. it was this moment that has left scientists all aflutter. high speed cameras confirming
if you look at their wings, you can see they are very large and broad compared to the size of their body and aren t considered to be very aerodynamic. but this to make of clapping and cupping now appears to have given them an evolutionary advantage. thinking is this technique developed by the humble butterfly could be applied to modern tech allergy to make drones and underwater vehicles faster, travel further and last for longer. laura foster, bbc news. just a reminder that later today in washington, it will be the inauguration, handover of powerfrom president biden. the time now in washington, just after half past midnight. we are in the final 12 hours of the trump presidency. a changeover at 12 noon exactly local time. changeover at 12 noon exactly localtime. 0f changeover at 12 noon exactly local time. of course, very different inauguration one we have ever seen or be extensive
it was this moment that has left scientists all aflutter. i speed cameras confirming what had been suspected for half a century, that butterflies don t just flap their win wings but clap them together. there are taxable wings bending to form a cup pocket about. when they collapse, this trust is even stronger and more efficient. it s only now thanks to modern technology and a swedish wind tunnel that we can see it. , . swedish wind tunnel that we can see it. v .. . swedish wind tunnel that we can see it. , ., . ., ., see it. it s a challenge to work with see it. it s a challenge to work with any see it. it s a challenge to work with any living - see it. it s a challenge to | work with any living flying animal but with butterflies it s maybe even more because they are smaller, they are fast in their behaviour, difficult to predict their behaviour and also when flying them in a wind tunnel, it s difficult to get them to behave as you want to, when you want to and also to fly whe