Saturday, December 08, 2007

The Mysterious Birth & Death of Gas Giants

A couple of pieces on gas giants (like Saturn and Jupiter) caught my eye today.

The first, by (via MSNBC), investigates the mystery of gas giants dying slow deaths as they spiral towards their host stars. While beautiful (these planets appear like shooting stars as their atmospheres are obliterated by a star’s energy), it’s a mystery how they end up so close (a fraction of an Astronomical Unit) to a star.

In our solar system, gas giants like Jupiter and Saturn are a few Astronomical Units (AUs) from the sun. (One Astronomical Unit is equal to the distance from the sun to the Earth.) And according to our best guesses on how gas giants form, it should be that way.

According to another article from, we used to believe gas giants formed the same way as other planets, by a process called “core accretion.” This process begins when dense matter (ice and rock, for example) smash and grind into a small protoplanet. Over time, the protoplanet may attract more dense matter and become a rocky planet like Earth; or, the theory went, it could attract gas and become a gas giant. Either way, the protoplanet would become a planet as it developed enough mass to carve out a stable orbit around the host star.

The problem was, computer models suggested it would take too long for a gas giant to form (or establish enough mass) before the fledgling protoplanet was sucked into the host star (or another planet).

While other theories have been developed, the birth of gas giants and how they end up in a death spiral so close to some stars remains a mystery.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.