0 -- A giant molecular cloud some 50 to 100 light years across orbits the nucleus of the Galaxy.  It is some -250° Celsius.  Some unknown even, possibly a nearby supernova, triggers the cloud's gravitational collapse.

2,000,000 -- A multitude of nuclei have developed within the cloud as it continues to collapse under its own gravity.  Hundreds to thousands of these exist, and one of them, of an average size of a tenth of a light year in diameter (more than a hundred times the present orbital diameter of Pluto), is destined to become the Sun.  As this nuclei collapses, its inner regions begin to warm, while the outer areas remain dark and cold.  This is the Solar Globule.

2,030,000 -- The core of the solar globule begins to take a definite shape, being a gargantuan ball the size of present day Pluto's orbit.  Its surface is too cold to emit light, but the central regions have reached 10,000° Celsius, with the molecules there splitting into hydrogen.  This is the protosun, and it had developed a marked rotation, which continued to speed up as the protosun began to shrink and grow denser and hotter.

2,130,000 -- The collapsing protosun has become a swollen semi-spherical mass, flattened at the poles by rotation.  Its surface temperature allows the body to glow visibly for the first time.  Its diameter is some 100 million kilometers, roughly the size of Mercury's orbit.  Also, the infalling matter has been flattened into a huge pancake of turbulent gas and dust that extends to the very surface of the protosun, but it flares vertically at the edges.  This is the solar nebula, and measures some 100 to 200 AU in diameter.  Near the center of the disk, close to the seething protosun, the gas and dust may be exceeding 2,000° Celsius, enough for it to emit its own visible light.  By now much of the globule has been consumed, and the newly forming star is revealed to the exterior cosmos for the first time.

2,200,000 -- The solar nebula begins to condense as molecules begin to form silicates and ices.  These particles collide with each other further, and fairly gently, forming a nebula filled with pebble-sized chunks of rubble -- rocky and metallic close in to the protosun, and icy beyond the so-called snow line, some 5 AU from the center of the nebula.

2,201,000 -- Through the many collision of the nebula particles, the majority of these primordial fragments have become concentrated near the mid-plane of the disc.  Being concentrated in a smaller area, they grow faster and aggregate into worldlets several kilometers in diameter.  These bodies have a greater amount of gravity, and thus begin to aggregate even quicker, eventually attaining the size of the Moon or so.  Hundreds of thousands of such worlds now exist.

2,300,000 -- A protoplanet some 20 times more massive than the Earth forms at the snow line.  It is a giant ball of ice and rock, and formed quickly because of the wealth of icy materials available, as opposed to the more scarce  inward silicates.  At its size and mass, it begins to collect the surrounding gases, principally hydrogen and helium, and gains dramatically in mass and size.  This will become the planet Jupiter.  At the same time, its Galilean moons also form.

3,000,000

• The protosun has shrunk to a few solar radii and has a surface temperature of some 5 million degrees Celsius, with a surface temperature of 4,500° Celsius.  It has become a T-Tauri star, with its earliest form of solar activity driven largely by massively powerful magnetic fields.  Its rotation is some 8 days long, with the mighty magnetic field plowing into the protoplanetary disc and dragging large chunks of its to the solar surface.  In response, the surface of the sun emitted large, violent flares that are the hallmark of T-Tauri stars.  The sun appears larger and cooler, as it is still collapsing.  Surface sunspots are huge, often covering significant portions of a given hemisphere.  As soon as the T-Tauri stage is begun, a massive solar wind races outward at some 200 kilometers per second.  Being channeled through the powerful magnetic field, a bipolar flow of gas rushes away from the star, extending trillions of kilometers into space.  This is called a Herbig-Haro object.
• As the T-Tauri phase rages on, the massive stellar winds clear out the pre-solar nebula of the light weight gases, blasting them into interstellar space.  Robbed of raw materials, the proto-Jupiter ceases its growth and begins to cool.
• Further out, Saturn has been forming much as Jupiter, but at a slower rate, and it too ceases its growth.

3,010,000 -- The massive solar wind ceases as the sun's mass stabilizes.  But the diameter continues to shrink under the force of gravity, and the surface temperature continues to move towards its modern levels.  This post-T-Tauri phase would last several million years as the sun moved towards its full maturity.

5,000,000 -- Further outward, two ice-cores begin to gather their own stockpiles of gas and dust, albeit at a slower rate because of slower orbital speeds and a scarcity of materials to begin with.

10,000,000

• The growth of Uranus and Neptune largely ceases.
• In the inner solar system, four dominant planetoids begin to appear.  these will become Mercury, Venus, Earth, and Mars.  At this point, however, they have only achieved half of their present day masses.  As time goes on, they grow more and more slowly due to the lack of materials, and the fact that the larger a body becomes, the lesser effect future impacts have on the building process.

10-100,000,000 -- A massive impact with a body half of its size blasts away Mercury's rocky mantle, leaving behind a much smaller world with a tremendously large iron core and a rather eccentric solar orbit.

30-50,000,000 -- (Note:  there is some dispute on this time frame)  The sun's contraction finally comes to an end as hydrogen is converted to helium at the core, and a hydrostatic equilibrium is achieved.  The sun has thus entered into the main sequence portion of its lifespan, and appears much as it does today.

100,000,000

• While the solar nebula is relatively sparse, the solar system is still littered with debris that had not yet been either ejected from the system or consumed by growing worlds.  This material is the source for the beginning of the Heavy Bombardment Era.
• The terrestrial planets finally achieve their present day sizes and masses.
• The terrestrial worlds begin to replace their primordial atmospheres with gases belched out from within themselves via volcanism.  These secondary atmospheres are marked by carbon dioxide, nitrogen, water vapor, and a few other compounds.

200-300,000,000 -- The Earth's oceans form during torrential global rainstorms after the surface finally drops below the boiling temperature of water.

860,000,000 -- The Caloris Basin on Mercury is formed.

1,300,000,000 -- Most of the primordial planetesimals and other interplanetary debris are gone, and the Heavy Bombardment Era ends.

1,600,000,000 -- A near-Mars-sized object gives the Earth a glancing strike.  The result is the beginning of the formation of the moon.

1,800,000,000 -- The Moon is no longer largely molten, and has begun to settle down into the largely dead world we know today.

2,660,000,000 -- Photosynthesis begins to release oxygen into the secondary atmosphere.

3,660,000,000 -- Oxygen levels reach ten percent of modern levels on Earth.

4,060,000,000 -- Oxygen levels reach their present day level.

4,660,000,000 -- The modern solar system is in place.

5,660,000,000 -- The sun's luminosity has grow by some 10 percent.  On Earth, the ice caps and oceans slowly begin to evaporate away in a moist greenhouse effect.

7,660,000,000 -- Up until life has only been able to survive in the insulating oceans.  But at this point, the oceans begin to disappear on a large scale, and with them goes the last of Earth's life.

8,160,000,000 -- The sun's luminosity has grown to 40% of its present levels, and Earth is now bone dry, lost within a massive greenhouse effect.

10,900,000,000 -- The sun leaves the main sequence.  Hydrostatic equilibrium is lost and the core shrinks, and an unused reservoir of hydrogen begins to burn (this hydrogen was previously at the outskirts of the core, where it was too cool to fuse).  The core continues to shrink, but the sun itself expands and becomes hotter.  The outermost parts of the sun, however, are cooler and redder than before, and as a whole it is some 1.6 times larger than its present day diameter.  It is now a subgiant star.

11,600,000,000 -- The sun's surface has cooled to 4,900° Celsius, and the energy deep within is trapped.  This internal pressure causes the sun to expand dramatically.

12,200,000,000 -- The sun has swollen to 160 times its present diameter, and its surface has cooled to about 3,100° Celsius.  It is red and cool, but its large surface area makes it very bright.  It has become a red giant.  Mercury has been consumed.  Venus might escape, as its orbit will expand with the sun's diameter, as will all the planets' orbits.

12,233,000,000 -- The sun attains a temperature of 100 million degrees, and helium begins to fuse in the Helium Flash.  So violent is this that the core ceases its collapse and the sun shrinks to about 10 times its current diameter.  Hydrostatic equilibrium is again achieved.

12,343,000,000 -- The helium core is exhausted, and it begins to shrink, while the size of the sun itself begins to expand, and much more dramatically and quicker than before.

12,363,000,000 -- The sun expands to its maximum extent, some 180 times it current size, and is 3,000 times brighter.  Again the planets are edged outward, and once more Venus might just survive the expansion.  Some of the outer planets' moons will thaw, and worlds such as Europa or Titan might sport water oceans, and possibly primitive life.

12,365,000,000 -- The sun suffers the first of four core temperature fluctuations and swells up to 300 million kilometers in diameter, the momentum of which carries away the outermost layers.  This is the first expulsion of material that will eventually become a visible planetary nebula.

12,365,100,000 -- The Sun suffers its second pulse.

12,365,200,000 -- The sun suffers its third pulse.

12,365,300,000 -- The sun suffers its fourth and final pulse.  By now it retains only about half of its original mass, and the core is exposed.  Waves of intense ultraviolet radiation stream out from the naked core, ionizing the previously expelled gas in a dazzling display of color -- a planetary nebula.

12,365,310,000 -- The sun's planetary nebula, a few tenths of a light year in diameter, fades away as it grows too far and too dispersed to be effected by the sun.  What is left is the naked core of the sun -- a contracted and diminutive body known as a white dwarf.  At this initial point, it has a surface temperature of 120,000° Celsius and a luminosity of 35 times that of today's sun.  But it is barely 1.5 times the diameter of Earth.  A long period of cooling sets in.

22,000,000,000 -- The surface of the white dwarf sun has cooled to about 3-4,000° Celsius, and looks distinctly red

100,000,000,000 -- The last of the sun's illumination fades, and what is left is a black dwarf.