He actually helped to make a big bang but had some regrets.

Mark Oliphant.     Boy, that one was a bit harder.

You have him Sheba most of us recognise him as an older man. Over to you for a pic.

Sir Marcus Laurence Elwin "Mark" Oliphant, AC, KBE, FRS, FAA, FTSE (8 October 1901 14 July 2000) was an Australian physicist and humanitarian who played an important role in the first experimental demonstration of nuclear fusion and in the development of nuclear weapons.

Born and raised in Adelaide, South Australia, Oliphant graduated from the University of Adelaide in 1922. He was awarded an 1851 Exhibition Scholarship in 1927 on the strength of the research he had done on mercury, and went to England, where he studied under Sir Ernest Rutherford at the University of Cambridge's Cavendish Laboratory. There, he used a particle accelerator to fire heavy hydrogen nuclei (deuterons) at various targets. He discovered the respective nuclei of helium-3 (helions) and of tritium (tritons). He also discovered that when they reacted with each other, the particles that were released had far more energy than they started with. Energy had been liberated from inside the nucleus, and he realised that this was a result of nuclear fusion.

Oliphant left the Cavendish Laboratory in 1937 to become the Poynting Professor of Physics at the University of Birmingham. He attempted to build a 60-inch (150 cm) cyclotron at the university, but its completion was postponed by the outbreak of the Second World War in Europe in 1939. He became involved with the development of radar, heading a group at the University of Birmingham that included John Randall and Harry Boot. They created a radical new design, the cavity magnetron, that made microwave radar possible. Oliphant also formed part of the MAUD Committee, which reported in July 1941, that an atomic bomb was not only feasible, but might be produced as early as 1943. Oliphant was instrumental in spreading the word of this finding in the United States, thereby starting what became the Manhattan Project. Later in the war, he worked on it with his friend Ernest Lawrence at the Radiation Laboratory in Berkeley, California, developing electromagnetic isotope separation, which provided the fissile component of the Little Boy atomic bomb used in the atomic bombing of Hiroshima in August 1945.

After the war, Oliphant returned to Australia as the first director of the Research School of Physical Sciences and Engineering at the new Australian National University (ANU), where he initiated the design and construction of the world's largest (500 megajoule) homopolar generator. He retired in 1967, but was appointed Governor of South Australia on the advice of Premier Don Dunstan. He assisted in the founding of the Australian Democrats political party, and he was the chairman of the meeting in Melbourne in 1977 at which the party was launched. Late in life he witnessed his wife, Rosa, suffer before her death in 1987, and he became an advocate for voluntary euthanasia. He died in Canberra in 2000.

https://en.wikipedia.org/wiki/Mark_Oliphant

Thanks Sandy.  This should be easier. 

I know who that is I will wait to see if someone else wants a go

Right you are Jack.  Who have you got ?

Christopher D'Olier Reeve was an American actor, writer and director. He was best known for playing DC comic book superhero Superman, beginning with the acclaimed Superman, for which he won a BAFTA Award.

Thanks Sheba. OK all. Who is this?

Cheers.

He would be the Antarctic explorer,Sir Douglas Mawson. 

G'day BG. Yep that's him. Who do you have for us?

Cheers.

Sir Douglas Mawson OBE FRS FAA was an Australian geologist, Antarctic explorer, and academic. Along with Roald Amundsen, Robert Falcon Scott, and Sir Ernest Shackleton, he was a key expedition leader during the Heroic Age of Antarctic Exploration.

Thank You Jack. Here's a popular guy in his time !!

Wouldn't have expected him to last this long.   Singer, Frankie Laine.

Yes, too easy Sheba. Over to you:

Thanks BG.  Who is this ?  Easy again. 

I'll probably kick myself, he looks familiar but I can't place him.

sandman55 wrote:

---

I'll probably kick myself, he looks familiar but I can't place him.

---

 I'm sure you will Sandy.    [Kick yourself, that is.]

He's not a Polly he's an actor I'll have to put my thinking cap on

I've tried Googling American actor of the 90's,Detective TV series and tried other decades without success I had better do some chores like feeding the chooks

If I remember rightly, he did have his own Detective TV series, but think Westerns.

Oooo that was a hard one I knew his face but I didn't know his name I knew I had seen him in a TV series. Robert conrad

I knew you'd know him.  Over to you Sandy.

Robert Conrad (born Conrad Robert Falk; March 1, 1935 February 8, 2020) was an American television series and movie actor. He also hosted a two-hour national radio show. He portrayed Secret Service Agent James West in CBS' TV show The Wild Wild West.He also played an American spy in the series Assignment Vienna.He was born in Chicago.. In 2003, Conrad was involved in a car accident

Thanks Sheba, there are some actors that you watch but don't bother to find out their names. This guy falls into that category and if you don't get him you will kick yourself later.

  Got my kicking shoes on already Sandy.  If some-one else doesn't get him first, this might take a while.

He played the part of a dentist in an Australian comedy series.

If I'm right, Robert Lindsay.  If not this will take a hell of a lot longer..  

No but this might give it away. In the comedy series he was the well off selfish dentist in the family leaving his younger brother as carer for mum.

Not to me mate.  I don't normally watch Aussie Comedy.  Hope some-one else does, or we're stuck here for a long while.

I'll give it one more try.    --------------------------  Sorry, but Mr. Google is no help at all.