0:00:04 > 0:00:05Ricky here with Saturday's Newsround.
0:00:05 > 0:00:06On the way:
0:00:06 > 0:00:09Could we be close to finding aliens?
0:00:09 > 0:00:18And do farms need to be in the countryside?
0:00:22 > 0:00:25First today, one of sport's greatest superstars Muhammad Ali
0:00:25 > 0:00:28has died aged 74.
0:00:28 > 0:00:30The boxer was famous around the world, but not
0:00:30 > 0:00:32just for his sport.
0:00:32 > 0:00:34We've been taking a look back at his life and why
0:00:34 > 0:00:37he was so important.
0:00:37 > 0:00:40I'll whoop any man in the world and I want everyone out
0:00:40 > 0:00:43there on TV to know it, I am the greatest.
0:00:43 > 0:00:47Muhammad Ali, the world's most famous boxer.
0:00:47 > 0:00:48He's got him.
0:00:48 > 0:00:50Born with a different name, Cassius Clay,
0:00:50 > 0:00:54in Kentucky in the US in 1942.
0:00:54 > 0:00:56He first achieved fame when he won gold
0:00:56 > 0:01:00at the Rome Olympics in 1960.
0:01:00 > 0:01:04He was famous for the way he talked and the things he said.
0:01:04 > 0:01:05Put him in the hospital!
0:01:05 > 0:01:06He has never been stopped.
0:01:06 > 0:01:09Oh, I'm so great.
0:01:09 > 0:01:11He won his first world heavyweight title at the
0:01:11 > 0:01:14age of just 22.
0:01:14 > 0:01:17But Muhammad Ali was more than just a boxer.
0:01:17 > 0:01:19He campaigned for civil rights at a time
0:01:19 > 0:01:23when black people in America were treated differently.
0:01:23 > 0:01:25The boxer converted to Islam and changed
0:01:25 > 0:01:29his name from Cassius to Muhammad Ali.
0:01:29 > 0:01:33He spoke out about racism and the world listened.
0:01:33 > 0:01:35One of his most famous fights was nicknamed the Rumble in
0:01:35 > 0:01:37the Jungle.
0:01:37 > 0:01:43It took place in 1974 against this man, George Foreman.
0:01:43 > 0:01:46If you think I whooped Sonny Liston, you wait until I get George Foreman.
0:01:46 > 0:01:49He talks too much, he's ugly, he's pretending,
0:01:49 > 0:01:52I'm the true champion and they make me the underdog.
0:01:52 > 0:01:56Muhammad Ali won.
0:01:56 > 0:01:57He just beat himself out.
0:01:57 > 0:02:01He was so tired he just fell on the ropes.
0:02:01 > 0:02:05I said, man, this is the wrong place to get tired!
0:02:05 > 0:02:08In 1984, the boxer became unwell.
0:02:08 > 0:02:11He was diagnosed with Parkinson's, a condition in which part
0:02:11 > 0:02:14of the brain becomes damaged.
0:02:14 > 0:02:16It made life difficult for the boxer but he
0:02:16 > 0:02:18didn't give up.
0:02:18 > 0:02:22In 1999, Muhammad Ali won the BBC Sports Personality
0:02:22 > 0:02:24of the Century.
0:02:24 > 0:02:28He got more votes than the rest of the contenders put together.
0:02:28 > 0:02:30I had a good time boxing.
0:02:30 > 0:02:35I enjoyed it and I may come back!
0:02:35 > 0:02:38He is known all over the world and will
0:02:38 > 0:02:40be remembered for being the greatest.
0:02:40 > 0:02:46I am the king of the world.
0:02:46 > 0:02:48Next, is there life beyond our planet?
0:02:48 > 0:02:50That's what scientists are aiming to find out with the
0:02:50 > 0:02:52Square Kilometre Array project.
0:02:52 > 0:02:55It's a huge radio telescope which will be able to search further
0:02:55 > 0:03:03into space than ever before.
0:03:11 > 0:03:15Aliens.
0:03:15 > 0:03:17Are they really out there?
0:03:17 > 0:03:23If so, are we ever going to find them?
0:03:23 > 0:03:25The universe is vast.
0:03:25 > 0:03:28Our solar system is just one of the solar systems around the sun
0:03:28 > 0:03:30which is one star amongst millions of
0:03:30 > 0:03:34stars in the galaxy and our galaxy is one among the millions of
0:03:34 > 0:03:37galaxies in the universe, so why not?
0:03:37 > 0:03:40Maybe there is light somewhere in another solar system in another
0:03:40 > 0:03:47galaxy.
0:03:47 > 0:03:48-- life.
0:03:48 > 0:03:51That's what scientists are trying to find out with the help of
0:03:51 > 0:03:52these.
0:03:52 > 0:03:54This is the Square Kilometre Array project.
0:03:54 > 0:03:56When it is finished, it will be the world's most powerful
0:03:56 > 0:04:00audio telescope, so sensitive that it will be able to detect a signal
0:04:00 > 0:04:02from a planet that is tens of light years away.
0:04:02 > 0:04:07These telescopes are listening for intelligent life and
0:04:07 > 0:04:10that is why they have decided to build them here.
0:04:10 > 0:04:12What makes this place in South Africa perfect is
0:04:12 > 0:04:16that there are no radio waves around to mess up the signal.
0:04:16 > 0:04:19No microwaves, no mobile phones.
0:04:19 > 0:04:22I have had to turn mine off.
0:04:22 > 0:04:23Every day these dishes are collecting massive
0:04:23 > 0:04:27amounts of data.
0:04:27 > 0:04:29Which will eventually be processed by a
0:04:29 > 0:04:33supercomputer in the UK.
0:04:33 > 0:04:36Where experts will look for any signs of life.
0:04:36 > 0:04:40How do you go about looking for alien signals?
0:04:40 > 0:04:42You've got big telescopes like that and they can listen in the
0:04:42 > 0:04:47universe and listen for radio signals from other planets where we
0:04:47 > 0:04:50hope they also have radio signals and maybe we can detect some of
0:04:50 > 0:04:52these signals.
0:04:52 > 0:04:54How would we know that aliens have tried to contact us?
0:04:54 > 0:04:57We are looking for intelligent signals, not from nature but made by
0:04:57 > 0:05:01intelligent creatures.
0:05:01 > 0:05:04Will we ever be able to find an alien?
0:05:04 > 0:05:05I certainly hope so.
0:05:05 > 0:05:08I hope to find them once in my lifetime, it will be
0:05:08 > 0:05:09such a big discovery.
0:05:09 > 0:05:12But it could take a long time and also it can take long
0:05:12 > 0:05:14to communicate with them because the
0:05:14 > 0:05:18signals take maybe years to go to the civilisation and also years to
0:05:18 > 0:05:21come back so one simple question and answer
0:05:21 > 0:05:25could take 40 years.
0:05:25 > 0:05:28Of course there is no guarantee that other civilisations exist beyond our
0:05:28 > 0:05:31world but if they do, it might not be long before
0:05:31 > 0:05:36SKA finds them.
0:05:36 > 0:05:38When you imagine a farm, you probably think of cows,
0:05:38 > 0:05:41sheep and the countryside but a farmer in the Netherlands has
0:05:41 > 0:05:45opened up the largest urban farm in Europe in an old factory.
0:05:45 > 0:05:49The urban farm is designed to be sustainable with no waste and uses
0:05:49 > 0:05:55fish to produce the fertiliser to help grow the plants.
0:05:55 > 0:06:01That's all from me, I'm back tomorrow just before 10.