The Really Big Questions

Why blog about the universe, instead of some other topic?

It's quite simple. There is no other topic.

Galaxies like grains of sand in this Hubble Ultra Deep Field image

The big questions left for science to answer can be counted on one hand. Once these five questions have been answered, those proposing that science has come to an end will have a strong case. It may be just that the rate of discovery is slowing. The five questions are:

1. What is the origin of the universe? It's probable that this question isn't even stated correctly. We're always told 'what came before the Big Bang' is a meaningless question due to the elastic and contingent nature of time. It is also possible that the 'why' in 'why is there something rather than nothing' and 'what is the meaning of the universe' are also meaningless, two of the many examples in philosophy where questions can be stated that are grammatically and logically correct, but irrational nonetheless e.g. what is the meaning of a cloud?

When formulating these fundamental questions, one should be careful in expunging all presuppositions. 'What is the meaning of life' presupposes that there is a meaning to know. 'Why is there something rather than nothing' presupposes that something needs a greater degree of explanation than nothing. Why should this be the case when there are mathematical or logical truths that exist independently of the universe? Isn't nothing more improbable than something? Peter Atkins, in his new book On Being, has playfully speculated that the universe arose ex nihilo out of some Platonic or Euclidean mathematical axioms. Any universe that is logically possible will exist by necessity. The use of the term universe can be sufficiently broad to include multiverses that vary in their physical constants and laws.
In any case, one thing we can be sure of is that we're unlikely to resolve this in our lifetimes, possibly ever.
That was the hard one. Now lets move on to the 'easy' questions.

2. How can the subjective experience of consciousness arise from inanimate matter? Our brains are just specific combinations of protons arranged in C, O, H, N, Ca, K, etc configurations. Is consciousness simply some emergent function of specific complexity? Any materialist has to agree. Will a sufficiently complex computer be self-aware? Is agency an illusion i.e. an afterglow our brains give us just to delude us into thinking we're calling the shots? We don't even know how to formulate the question correctly or even have a consensus on how to tackle this issue e.g. mapping the neural correlates of consciousness or AI research or studying stroke victims or genetic differences between primates and humans?

3. How did life get started? We think we know what the answer looks like: some auto-catalysing molecule that existed in some deep-sea vent environment (white smoker, black smoker) that was subject to high pH gradients, high temperature gradients, high pressure gradients, and lots of trace elements passing through concentrating microtubules and mixing over hundreds of millions of years sometime about 3.5 - 4 billion years ago.

4. Is there life elsewhere in the universe? Sending probes to detect bacterial life below the Martian regolith or beneath the Europan ice sheath will be the most likely opportunity for discovering ET life in our own solar system. We may also detect free oxygen in the atmospheres of distant exoplanets within a few decades, a strong indicator of life, but not conclusive. The present consensus seems to be that the universe is teeming with bacterial life (as bacteria is hardy and got started on Earth relatively quickly) while intelligent life may be rare (because it only happened once on Earth and very late in the game, and because SETI haven't detected any signals yet). It all depends how rare the Earth and our solar system are (e.g. stability of the sun, planetary configuration, presence of the Moon, tectonics, size & composition of the Earth, galactic habitable zone, etc). The SETI Institute figure that once a proper 20 year broadband survey is complete (2030s), we'll have a better idea of how to constrain the many probabilities of the Drake equation.

5. What is the nature of dark matter and dark energy? Even though we embarrassingly don't know what 96% of the universe is made of, it's still only two mysteries. Dark matter will probably be solved first in the next few decades e.g. probably just some form of ghostly neutrino-like sub-atomic or super-symmetric particle.

Questions 2-5 may be possible in principle. In practice, perhaps we can only hope for partial, inconclusive, and unsatisfactory answers to questions 3-5 in our lifetimes. Some may take centuries to resolve. If that's so, we'll just have to get used to living with uncertainty with no foreseeable prospect of resolution to these questions. There will still be relatively minor problems to address: can we cure ageing, can we get off this planet once the sun gets too hot, and can we solve our energy needs?