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April 03, 2011

Contaminated White Dwarfs a Sign of Past Terrestrial Planets

This article is somewhat contradictory to the last entry. It says that terrestrial planets may not be found so easily around white dwarfs and that if they do exist, they probably don't support life. However, it's possible that solar systems like ours have existed in the past around these white dwarfs. Normally, white dwarfs contain only hydrogen and helium, but sometimes heavier elements like calcium are mixed in there. Where did these elements come from? Most likely from dust from asteroids that are leftover pieces of building blocks for terrestrial planets. This dust rains down on the white dwarf, adding new elements to it. These elements can be found by studying the infrared radiation of the star, and by knowing which elements exist there, we can know determine whether or terrestrial planets exist or have existed around the star that could be like the planets in our own solar system. This dust orbits around the star because the asteroids that used to be there were pulled apart by the tidal forces from the star.

Although it is interesting to determine where solar systems like ours have existed in the distant past, it seems slightly irrelevant if we cannot determine if the terrestrial planets that existed around these white dwarfs were like our own, and especially Earth. Perhaps there may be a way to determine if life had existed there before?


Posted by brdoss at April 3, 2011 11:12 AM


We can use telescopes and spectroscopic techniques to find the composition of the white dwarfs and the planets around them. Combined with data on their size, density, distance from their white dwarfs, and temperature, we could figure out how similar the planets are to the terrestrial planets of our solar system.

Posted by: stoneswt at April 3, 2011 07:35 PM

Interesting find, but I have to ask: what exactly is a white dwarf? Is it a type of star, or because it's technically dead is it classified as something else? I think it's an awesome prospect, that there might have once been a solar system just like our's long ago. But I don't quite understand from the article whether this is a new discovery or not. It seems as if we would've been aware of this type of thing long ago, especially if it's happening in our own galaxy. It'll be interesting to see how it plays out. I take it any terrestrial-like planet orbiting these dwarfs will have long since been dead, but I'm sure scientists will devise some way to figure out if they once harbored life.

Posted by: kailjoyb at April 4, 2011 02:29 AM

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