Cosmology Curiosity

The origin of the Universe

Where did the universe come from?

Many Christians will say that the Bible made it pretty clear -- 'God said'.

Some Christians will add that God may have used naturalistic means just the same.

The following summarizes what secular science thinks insofar as creation of the cosmos is concerned. From Cornell University's Curious About Astronomy?:

'Assuming the Big Bang is a valid theory of the creation of Earth and the Universe, then where did the original mass come from, that formed everything that we see today?

'First of all, note that mass and energy are equivalent. So, the total mass of the Universe need not be conserved even though the total energy (taking into account the energy that is equivalent of the mass in the Universe) is conserved. Mass and energy are related by the famous equation E=mc². Hence if there is enough energy, photons can create matter-antimatter pairs. This is called pair production and is responsible for the mass in the Universe.

'As to where everything came from, there is no conclusive opinion. One idea was that the Universe was created from vacuum. This is because according to quantum theory, the apparently quiescent vacuum is not really empty at all. For example, it is possible for an electron and a positron (a matter antimatter pair) to materialize from the vacuum, exist for a brief flash of time and then disappear into nothingness. Such vacuum fluctuation cannot be observed directly as they typically last for only about 10^-21 seconds and the separation between the electron and positron is typically no longer than 10^-10 cm. However, through indirect measurements, physicists are convinced that these fluctuations are real.

'Hence, any object in principle might materialize briefly in the vacuum. The probability for an object to materialize decreases dramatically with the mass and complexity of the object. In 1973, Edward Tyron proposed that the Universe is a result of a vacuum fluctuation. The main difficulty of this proposal is that the probability that a 13.7 billion year old Universe could arise from this mechanism is extremely small. In addition, physicists would question Tyron's starting point: if the Universe was born from empty space, then where did the empty space come from? (Note that from the point of view of general relativity, empty space is unambiguously something, since space is not a passive background, but instead a flexible medium that can bend, twist and flex.)

'In 1982, Alexander Vilenkin proposed an extension of Tyron's idea and suggested that the Universe was created by quantum processes starting from "literally nothing", meaning not only the absence of matter, but the absence of space and time as well. Vilenkin took the idea of quantum tunneling and proposed that the Universe started in the totally empty geometry and then made a quantum tunneling transition to a non-empty state (subatomic in size), which through inflation (the Universe expands exponentially fast for a brief period of time which causes its size to increase dramatically) came to its current size.

'Another idea is from Stephen Hawking and James Hartle. Hawking proposed a description of the Universe in its entirety, viewed as a self-contained entity, with no reference to anything that might have come before it. The description is timeless, in the sense that one set of equations delineates the Universe for all time. As one looks to earlier and earlier times, one finds that the model Universe is not eternal, but there is no creation event either. Instead, at times of the order of 10^-43 seconds, the approximation of a classical description of space and time breaks down completely, with the whole picture dissolving into quantum ambiguity. In Hawking's words, the Universe "would neither be created nor destroyed. It would just BE."

'So, the origin of mass in the Universe and the Universe itself is quite speculative at this point. If you are interested, you can read Alan Guth's book "The Inflationary Universe", page 271-276. You can also read Hawking's "A brief history of time: From the Big Bang to black holes" page 136.' [emphases supplied]

The article was written by Jagadheep D. Pandian.

Looks like an ex nihilo creation would still be the most logical scenario.

[Image: Nick Wright/ INT Photometric Hα Survey of the Northern Galactic Plane]

cosmology

The Sun as a black hole, Part 2

More on the hypothetical scenario, this time from Bad Astronomy.

If the Sun were to become a black hole, what would it be like?

'The gravity of an object depends on two things: the mass of the object, and the distance you are from that object. Isaac Newton showed (using calculus) that as long as you are outside a spherical object, gravitationally you can treat that object as a point mass. In other words, as you stand on the surface of the Earth, the gravity of the Earth pulls you as if all the mass of the Earth were concentrated at a point in its center. As long as you are outside the surface of the Earth this will be true. If you keep the Earth's mass the same and shrink it to the size of a golf ball, you will feel the same gravity as long as you stay more than the Earth's old radius away (about 6400 km).

'The same applies if the Sun were to collapse into a black hole. Its mass is still the same, and the distance to the Sun would not change. Therefore, the gravity of the Sun felt at the Earth would remain the same. The gravity, in fact, would feel the same to you as you approach the erstwhile Sun all the way to where its surface used to be (about 700000 km from the center).

'The situation changes when you get closer than where the surface used to be. Imagine you dig a hole in the Earth 100 km deep. Using some calculus, it can be shown that the mass of the Earth outside your radius (that is, the radius of the Earth minus 100 km) no longer has any net force on you. You will feel lighter. This will continue as you dig deeper, until you are at the center of the Earth. Then all the mass is outside of you, and has no net force on you. You'll be weightless! (Actually, the situation is a bit more complicated: the Earth's crust is somewhat less dense than the parts beneath it, so as you dig down, at first you actually will get heavier as you approach the more dense regions, but as you go down deeper you will start to get lighter). So it is with the black hole Sun. As you approach, the gravity will feel just like the old Sun's, until you get closer than about 700000 km. Before, you would start to get lighter as you pierced the surface, but now the surface is still below you! The gravity gets stronger. And stronger, and stronger, and STRONGER, until you are just above the surface. At this point the gravity is so strong the tides from the black hole will rip you apart. Heavy, dude.

'One more note: the Sun, by itself, cannot turn into a black hole. The above is an imaginary exercise. Stars that turn into black holes are typically either much more massive than the Sun (at least 8 times as much) or must be part of a binary system, which the Sun is not. We don't need to worry about this happening to us, but it does make a fun thought experiment!'

The above was quoted in full from Bad Astronomy's article, What if the sun collapses into a black hole?

[Image: NASA]

Related post: If the Sun were a black hole

black hole, cosmology, event horizon, sun

If the Sun were a black hole

The Sun cannot become a black hole because it doesn't have enough mass.

But if it were to become one, how large a black hole would it be?

The Sun is 1.4 million kilometers across. Said diameter is about 110 times the Earth's diameter. If the sun were a hollow sphere, it could fit more than a million Earths inside it.

Now if the Sun were a black hole it would just be 3 km (2 miles) across. The 3 km would be the diameter of the event horizon incidentally. From Curious About Astronomy?:

'When astronomers refer to the "size" of the black hole, they are talking about the event horizon. The event horizon refers to the location from the black hole where the escape velocity equals the speed of light. In other words, no particle (even light) can escape from within the event horizon. Mathematically, the size of the black hole is given by GM/c2 where G is the gravitational constant, M is the mass of the black hole and c is the speed of light.'

Would the Earth and all the other planets get sucked into the Sun-turned-black-hole? They won't. Because a black hole is not cosmic vacuum cleaner. Since the black hole Sun will still have the original mass, the laws of gravitation dictate that all planets will still revolve around it as usual.

On Earth thus, it will be dark and cold but the gravitationally, it will all be the same.

[Image by Lykaestria, per GNU Free Documentation license.]

Related post: Black hole misconception
Related post: The Sun as a black hole, Part 2

black hole, event horizon, sun

Christianity and the 'new earth'

Some have accused Christians of being indifferent on environmental issues. This arises because of the Christian doctrine about the imminent destruction of the cosmos.

Those few environmentally-indifferent Christians are mistaken anyhow. And it's because the final state of believers includes a restored heaven and earth.

Revelations 21:1 says: 'Then I [John the Beloved] saw a new heaven and a new earth, for the first heaven and the first earth had passed away, and there was no longer any sea.' II Peter 3:13 says the same thing: 'But in keeping with his promise we are looking forward to a new heaven and a new earth, the home of righteousness.'

Thus in the 'beginning God created the heaven and the earth' [Genesis 1:1] but such was marred by sin; in the end God is to restore the original creation into its former pristine state.

In between, man was tasked to look after and subdue the earth (responsibly, to meet his own needs).

Should a Christian go 'green' then? For so long as he does not regard environmentalism as a second religion, yes.

[Image by Luc Viatour, per Creative Commons Attribution ShareAlike license.]

Christian cosmology, Christian view, cosmology, envrironment

[Off-topic] Religious denominations' geography

The image above appeared on Strange Maps.

Please click the map for an enlarged view.

The map shows the leading church bodies in the US per county. County designations are based on the total number of adherents reported by each church body divided by the county population in 2000.

An excerpt: "Most of the other counties have Catholics as the most numerous congregation, leading to a somewhat misleading map. Catholicism very often is the biggest denomination by default, owing to the fact that their institutional unity boosts ‘market share’ but at the same time masks differences between different wings of the Roman church that are as great as between denominations of Protestantism that have separated over theological differences."

Baptists continue to be the largest denomination in the entire US, followed by Catholics, Lutherans, Methodists, and Latter-Day Saints.

Christians, denominations, geography, maps, region, religion, sects