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Strange New 'Twin' Worlds Found
toomanyairmiles writes "The BBC reports on the the discovery of 'twin worlds' which orbit each other, successfully blurring the line between planets and stars. 'Their existence challenges current theories about the formation of planets and stars.' according to the Journal of Science article which reports their existence. 'The pair belongs to what some astronomers believe is a new class of planet-like objects floating through space; so-called planetary mass objects, or "planemos", which are not bound to stars.'"
Anticipating a possible question: no, a previously-unknown population of "planemos" can't be the dark matter astronomers are searching for. First, there were enough of them to account for the huge mass of dark matter (some 95 percent of the mass of the universe), we would have seen a lot more of them by now. "Massive compact halo objects", or basically planetoids, brown dwarfs, neutron stars, etc. have been detected (via gravitational lensing), but they are known not to comprise the majority of dark matter due to such bounds on their total mass. Furthermore, from the effects of dark matter on structure formation in the early universe, the cosmic background radiation, and other factors, it is known that "normal" matter can't account for most of the mass of dark matter, either: most of it needs to be in the form of "weakly interactive massive particles" (sort of analogous to neutrinos, except much heavier).
technically they do... a planetary object by definition needs something to orbit.
What i think you meen is that a nebula of the right size can form a stelar object that doesnt have the mass for fusion.
pluto is thought to be a captured kuiper belt object,, meaning that some collision or gravitational interaction with a massive body brought it in towards the inner solar system, which explains its eccentric orbit which is also at a very high inclination to the plane of the ecliptic.
You are incorrect as to why the planets are on the same elliptical plane.
http://www.nineplanets.org/origin.html
#3 on that page is the step which explains why the solar system is on the same plane. Pluto being outside that plane is most likely it is actually a kupier belt object and was far enough out from the formation of our sun to not have fully fallen into the accretion disc.
More information is available at http://en.wikipedia.org/wiki/Accretion_disc
http://en.wikipedia.org/wiki/Protoplanetary_disc
The reason your explanation doesn't work for why the planetary bodies are on the same plane is because they are all in stable orbits. To plane out into a disc they would need to still be falling towards the sun.
Planetary rings are in the ring pattern because they follow the orbit of the object from which they were created, they are not collected and built up from smaller particles but probably the result of the destruction of a large object.
http://en.wikipedia.org/wiki/Planetary_rings
The researchers discovered the companion candidate in an optical image taken with ESO's 3.5-m New Technology Telescope at La Silla, Chile. They decided to take optical spectra and infrared images of the pair with ESO's 8.2-m Very Large Telescope to make sure that it is a true companion, instead of a foreground or background star that happens to be in the same line of sight. These follow up observations indeed confirmed that both objects are young, at the same distance, and much too cool to be stars. This suggests the two are physically associated.
While they are not sufficiently massive to spark fusion, they do, in fact radiate in the infrared range, due to gravitational contraction heating.
KFG
Ahh hmm. It was my understanding that the accretion disk of our solar system (the planets) formed due to the combination of gravity and inertia/velocity. I.E. that's why they're all in the same orbital plane.
The reason your explanation doesn't work for why the planetary bodies are on the same plane is because they are all in stable orbits. To plane out into a disc they would need to still be falling towards the sun.
But aren't they getting close to the sun all the time? In effect still falling towards it? Seems like it would be perpetual motion were they not?
TLF
I do not respond to cowards. Especially anonymous ones.
Six times the distance from the Sun to Pluto. If you're on one planet you might be lucky to see the tiny dot of the other planet in the night's sky... I don't recall if it said they were orbiting a star (for light) or not. So even the picture is misleading.
They both orbit around their common center of mass, as do all pairs of orbiting bodies. The moon and earth actually orbit around a point 4700km from the earths center.
"Prefiero morir de pie que vivir siempre arrodillado!"
I think that Wolfram is the only published and highly regarded scientist really trying hard to think outside of the box now days. If you study the last iterations of the theories of the Universe revolving around the earth, you will see what complexity in trying to make everything fit perfectly.
Information wants a fueled airplane waiting at the hangar and no one gets hurt.
Things moving in empty space come as close to perpetual motion as you're likely to get. However, the orbits of the planets are probably decreasing slightly over time due to the minor friction of the solar wind and mutual gravitational interactions with the other planets (especially Jupiter).
Also, tidal distortions have an effect which slows the rotation of planets down, especially if they have a relatively big moon orbitting them, until the rotational period and the orbital period match. For example, the moon always presents the same side towards the Earth because of tidal locking, and the Earth probably had about an 18-hour day some billion years ago, and will probably have a 30+ hour day in another billion years
"The human race's favorite method for being in control of the facts is to ignore them." -Celia Green