Could life on Earth survive without the Moon?

[wd40]

If the Moon were to suddenly disappear altogether/disintegrate in to particles/shoot off 5 million miles, what effect would it have on

- the Earth's orbit round the Sun e.g. would it move in or out or even destructively destabilise it?

- on the length of the Earth's day i.e. increase or decrease it?

- on the continued viability of life on Earth e.g. loss of nocturnal illumination and stopping of the tides?

[Jens]

(a) Substantially none.
(b) In the short term none.
(c) Difficult question. I'll defer to others.

And although you didn't ask, a bonus answer:
(d) The effect on music and literature would be devastating. What would we call that special walk that Michael Jackson used to do?

[kjupiterseven1541]

A. The orbit around the sun would be the same,but the earths axis or tilt would be unstable and this would effect the weather pattens around the world.
B.The earth,s day would still get longer but at a slower rate.
C.Life would still continue,but certain species like turtles,crabs,and others who use the the full moon to bred could be in trouble,as for the tides we would still have tides due to are sun,but on a much smaller scale.

[danscope]

The great ocean tides flush our rivers and harbors and estuarys each day and bring nutrient rich sea water back in return.
What a great gift that is. Boston harbor gets about a 9 foot tide. That's a lot of water in and out .

[cran]

If the Moon were to suddenly disappear altogether/disintegrate in to particles/shoot off 5 million miles, what effect would it have on

- the Earth's orbit round the Sun e.g. would it move in or out or even destructively destabilise it?

As far as I know, it would have a number of minor effects on the Earth's orbit; whether any of those effects would be noticeable to human senses or only to instruments might well depend upon the nature and energies involved in the Moon's disruption or displacement. The most obvious difference is that the Earth would no longer be a co-orbiting body, so that (roughly) 29 day wobble would no longer apply.

- on the length of the Earth's day i.e. increase or decrease it?

The rate of increase would be reduced proportional to the loss of tidal drag, but as the natural increase is already much less than detectable by human senses, it would require instruments to show that difference.

- on the continued viability of life on Earth e.g. loss of nocturnal illumination and stopping of the tides?

Overall viability (bioactivity) would not change. Speciation and extinction rate spikes would depend in part upon the adaptability of Moon/moonlight/tidal dependent species, and upon whether the Moon was disintegrated or displaced (a full Moon co-orbiting 5 million miles further away would still be a fairly bright night sky object - roughly 1/400th(?) as bright as it is now).

[Ivan Viehoff]

There's life in cracks between rocks quite some distance underground. It would need some enormous catastrophe to extirpate all life, something that substantially modified the environmental conditions well below the surface suddenly enough that the life couldn't migrate to somewhere else where it could find its necessary conditions.

There's a tendency to say "life on earth depends on X, therefore X is a necessary condition for life". This is not a valid argument. We cannot know whether, in the absense of X, life could have evolved to do without it.