In the history of science and technology, there are some cases, when scientists don't believe into something, which appear real later.

For example, Bill Gates was saying 640K is sufficient to any computer :)

Was such thing happen in the history of nuclear weapon? Did someone famous not believed into it?

UPDATE

May be some problems were regarded as unsolveable initially, for example obtaining pure enough fuel or handling undercriticall masses?

UPDATE 2

Urban legends also ok. For example, if it was popular opinion, that A said something impossible.

UPDATE 3

Let's try to narrow time. Let it be before discovery of neutron and fission (1932). Wasn't it possible to understand, that nucleus contain a lot of binding energy, but without knowing fission to doubt, it can be extracted?

In the history of science and technology, there are some cases when scientists did not believe something that later turned out to be real.

For example, Bill Gates was saying 640K is sufficient to any computer :)

Did such thing happen in the history of nuclear weapon? Did someone famous not believe nuclear weapons were possible?

UPDATE

Maybe some problems were regarded as unsolvable initially, for example obtaining pure enough fuel or handling undercritical masses?

UPDATE 2

Urban legends also ok. For example, if it was popular opinion that A said something impossible.

UPDATE 3

Let's try to narrow the time. Let it be before the discovery of neutron and fission (1932). Wasn't it possible to understand that that the nucleus contain a lot of binding energy, but not knowing about fission to doubt that it can be extracted?

In the history of science and technology, there are some cases, when scientists don't believe into something, which appear real later.

For example, Bill Gates was saying 640K is sufficient to any computer :)

Was such thing happen in the history of nuclear weapon? Did someone famous not believed into it?

UPDATE

May be some problems were regarded as unsolveable initially, for example obtaining pure enough fuel or handling undercriticall masses?

UPDATE 2

Urban legends also ok. For example, if it was popular opinion, that A said something impossible.

In the history of science and technology, there are some cases, when scientists don't believe into something, which appear real later.

For example, Bill Gates was saying 640K is sufficient to any computer :)

Was such thing happen in the history of nuclear weapon? Did someone famous not believed into it?

UPDATE

May be some problems were regarded as unsolveable initially, for example obtaining pure enough fuel or handling undercriticall masses?

UPDATE 2

Urban legends also ok. For example, if it was popular opinion, that A said something impossible.

UPDATE 3

Let's try to narrow time. Let it be before discovery of neutron and fission (1932). Wasn't it possible to understand, that nucleus contain a lot of binding energy, but without knowing fission to doubt, it can be extracted?

In the history of science and technology, there are some cases, when scientists don't believe into something, which appear real later.

For example, Bill Gates was saying 640K is sufficient to any computer :)

Was such thing happen in the history of nuclear weapon? Did someone famous not believed into it?

UPDATE

May be some problems were regarded as unsolveable initially, for example obtaining pure enough fuel or handling undercriticall masses?

In the history of science and technology, there are some cases, when scientists don't believe into something, which appear real later.

For example, Bill Gates was saying 640K is sufficient to any computer :)

Was such thing happen in the history of nuclear weapon? Did someone famous not believed into it?

UPDATE

May be some problems were regarded as unsolveable initially, for example obtaining pure enough fuel or handling undercriticall masses?

UPDATE 2

Urban legends also ok. For example, if it was popular opinion, that A said something impossible.