There are some obvious questions associated with the Solar System. The first might be ``how old is it?'' Stellar evolution theory says that

Sun about 5 billion years old, but that depends on how well we understand how stars work.

http://antwrp.gsfc.nasa.gov/apod/ap030320.html

Nicolaus Copernicus; Tokoh Heliosentris (1473-1543)

Nebular Hypothesis: A second theory is called the nebular hypothesis. In this theory, the whole Solar System starts as a large cloud of gas that contracts under self-gravity. Conservation of angular momentum requires that a rotating disk form with a large concentration at the center (the proto-Sun). Within the disk, planets form.

Immanuel Kant (1724-1804)

Adanya Kabut NebulaKabut itu berputar dengan kuat & terjadi pemadatan di bagian tengah

Di bagian tengah terbentuk Matahari dan di pinggirnya

terbentuk planet-planet

Planet-planet terus berputar dan membentuk orbit mengelilingi

Matahari

Maka terbentuklah Tata Surya

Protoplanet Hypothesis: The current working model for the formation of the Solar System is called the protoplanet hypothesis. It incorporates many of the components of the nebular hypothesis, but adds some new aspects from modern knowledge of fluids and states of matter.

Gerald P. Kuiper (1905-1973)

Teori Kuiper:

-Semesta terdiri dari formasi debu kosmik -Dua pusat memadat menjadi dua bintang, terdiri dari hidrogen -Pusat yang lebih besar memadat menjadi bintang tunggal -Bagian yang lebih kecil menjadi material Protoplanet -Protoplanet tersebut kemudian menjadi planet -Jika kekuatan dua bintang itu sama, maka akan terbentuk bintang ganda/kembar

How did the Solar System form? Any theory of the solar system formation must account for the obvious features we see, such as 1) the fact that solar system is a fairly flat place, with all the planets within a few degrees of the ecliptic and revolving in roughly circular oribts that are all going in the same direction, 2) the division between the small, rocky terrestrial planets in the inner part of the solar system, and the hydrogen-rich Jovian planets in the outer solar system, 3) the decrease in average planet density from the inner part of the solar system to the outer part, and 4) the existence of Bodes law, with each planet roughly twice as far from the Sun as the previous planet.

Thomas Chrowder Chamberline

(1843-1928)

There was encounter between the Sun and another star. In this scenario, the gravity of the passing star tears a succession of bolts from the solar surface. Bolts coming from the side nearer the star are thrown out to distances comparable with those of the giant plants, while those from the far side of the Sun are ejected less violently to the distances of the terrestrial planets. From the inner remains of these bolts formed the initial cores of the planets. The outer parts expanded and cooled into a huge swarm of solid particles spread out in a disk rotating about the Sun in a plane determined by the motion of the passing star. The cores gradually grew into planets by gathering in the planetesimals, most of the growth taking place in the outer parts of the Solar System where material was more plentiful. Eventually it became clear that, like other variants of the encounter idea, not enough angular momentum could be conveyed to the ejected material to explain the state of the Solar System as it exists today.

Encounter Hypothesis: One of the earliest theories for the formation of the planets was called the encounter hypothesis. In this scenario, a rogue star passes close to the Sun about 5 billion years ago. Material, in the form of hot gas, is tidally stripped from the Sun and the rogue star. This material fragments into smaller lumps which form the planets. This hypothesis has the advantage of explaining why the planets all revolve in the same direction (from the encounter geometry) and also provides an explanation for why the inner worlds are denser than the outer worlds.

James Jeans (1877-1946)

Pertemuan 2 bintang…

Susunan planet-planet seperti cerutu: kecil pada kedua ujungnya & besar di bagian tengahnya

Komar©November 2008