The puzzle of planet formation

planet-formation

“The formation of planets is one of the major unsolved problems in modern astrophysics.” That’s how Rafael Millan-Gabet at Caltech and John Monnier from the University of Michigan begin their account of how our understanding of planet formation is about to undergo a revolution.

Driving this change will be a new generation of telelscopes and techniques capable of measuring and in some cases imaging planet formation in action.

It’s worth pointing out the poverty of our current understanding. At the heart of the problem is the fascinating question: why are all the planets different?

The ones in our solar system ought to have formed out of the same stuff at more or less the same time and yet no two are alike. And now the extrasolar planets seem to be demonstrating a similar variety.

The  trouble is that astronomers have only the vaguest understanding of what goes on inside  the circumstellar discs where planets are supposed to form. They have little idea of the circumstances in which accretion dominates over gravitational instability, whether “dead zones” exist in circumstellar discs where planets cannot form or what mechanisms are at work in transporting angular momentum within early solar systems.  They don’t even know when planets form.

The new measurements that will be possible in the coming years should hep to answer at least of these puzzles. And that makes this an exciting field to be in. Watch this space for developments

Ref: arxiv.org/abs/0902.2576: How and When do Planets Form? The Inner Regions of Planet Forming Disks at High Spatial and Spectral Resolution

3 Responses to “The puzzle of planet formation”

  1. Jasper says:

    I was wondering if your blog does not have a spellcheck since you seem to make a lot of mistakes. Almost in all posts there are letters switched or added, e.g. telelscopes. I don’t want to nitpick but I was just wondering.
    I do like this blog and I read almost all posts. Keep up the good work!

  2. Zephir says:

    Problem of planet formation is just a smaller version of cosmological problem. The general question is, whether planets have appeared by gradual accretion of interstellar matter into larger objects, which have served like seeds – or whether these nuclei have appeared as a result of spontaneous condensation of finely divided remnants of supernovae explosion?

    The same problem exists in contemporary cosmology: were galaxies formed by (evaporation of) black holes, or were black holes formed by gravitational collapse of interstellar gas at the center of galaxies or dark matter clusters? This question isn’t so trivial, as it can appear for someone..

    http://www.nature.com/news/2009/090107/full/news.2009.6.html

    By AWT galaxies can be formed by evaporation of primordial black holes larger, then the human/CMB scale (1.7 cm or so, the lifespan of which roughly corresponds the age of observable Universe generation). Smaller black holes could appear by condensation of stellar gas and by mutual collisions of stellar black holes only. As the result, smaller galaxies usually lacks central black hole and they’re of rather spherical shape.

    The very same criterion can be applied for planet and planetoids formation. Only pieces larger then some 1.7 cm can serve as a nuclei for accretion and subsequent gravitational growth, or they would become dispersed by radiation pressure of CMB photons. The smaller pieces of matter tends to condense as a whole in large clusters, instead (large means > 1.7 cm).

    The 1.7 cm is wavelength, which enables energy to spread by slowest speed both at the water surface in capillary waves, both through cosmic space (in CMB photons). From AWT follows, larger objects tend to condense, while the smaller gets evaporate (a duality of thermodynamics time arrows). The objects, whose size corresponds roughly our size, or the size of CMB (relict gravitons) or the size of observable Universe from outside. This equilibrium can be observed inside of rain droplets, where the droplets smaller then 1.7 cm tends to evaporate, the larger droplets tends to fragments instead. The cells of living organisms above 1.7 cm scale are of concave shape, whereas the smaller one are rather spherical.

    By AWT these connections are consequence of observation (i.e. mutual interaction or interference) of Aether fluctuations by neural brain waves of the similar size – i.e. it’s just our size, what defines the critical curvature of observable Universe, which leads to evolution of maximal complexity and enthropy at the same time (simillia simmillibus creatur).

  3. [...] El rompecabezas de la formación de planetas,(en inglés) aquí. [...]