Celestia Forums

In terms of atmosphere, it depends on the mass of the planet. Super-Earths range from 2 to 10 times the mass of Earth (higher masses are possible if the star is exceptionally metal-rich). Since you're dealing with a planet covered in a global ocean of water, then the planet would be in the habitabil...

The planet could be a "hot Super-Pluto". As we all know, Pluto is a world composed of 50% rock and 50% ice. The newly discovered planet would be a much larger version of Pluto in terms of composition. The planet could have formed well beyond the snow line, so a significant portion of the p...

Orcus and Quaoar both have a moon, so their mass can be measured. No moon has been found around either Sedna or 2007 OR10, so their masses cannot be directly measured. Also, Sedna and 2007 OR10 are too small and too far away to have their size directly measured by HST. It will take the upcoming Jame...

Orcus will be the next object in the solar system to be recognized as a dwarf planet by the IAU. The mass, 6.32 x 10e20 kg, is squarely within the mass range for a dwarf planet. Even though Orcus turns out to have a smaller mass than Ceres, the world still has more than enough mass to achieve hydros...

Sirius is one of the worst candidates for having an Earth-like world. An orbit in the HZ of Sirius A would be dynamically unstable due to gravitational perturbations from the degenerate dwarf Sirius B. Such a planet would be catapulted out of the system by Sirius B in less than 1000 years. Also keep...

There are a number of things that can be inferred from what we know about COROT-7b. The density of COROT-7b (from mass and diameter) comes to 5.60 g/cm^3. This is practically identical to Earth, Venus, and Mercury. However, their compositions are different. Mercury has an extremely high iron content...

Actually, we already know of such a system. HD 98800 is a quadruple system of 4 solar type stars (spectral type K, most astronomers consider K dwarfs to be solar-type) arranged as a pair of doubles. The binary, 'HD 98800B', is surrounded by two debris disks. Although no planets have been found in th...

Even though an Earth-mass / Mars-mass binary is unlikely, it is possible, through the same mechanism that created the Pluto-Charon binary. This type of binary could be created by a collision. The hypothetical binary would be stable if the binary orbited an early F star. F stars are still considered ...

1.3 billion years is still a long time for tidal locking to take place. The issue that is brought up in the forums would only exist for systems that are extremely young, such as Beta Pictoris (about 8 million years old). As an example, some tidal lock times : Moon tidally locked to Earth...............

Before sounding the alarm on what could possibly happen, I think that it's worth noting that there are alternative explanations for why Betelgeuse has shrunk during the last 15 years. These are: 1 -- Long-term pulsation behavior. 2 -- The star isn't always spherical, creating the illusion of changin...

Gliese 581d may be the first Earth-like world found outside of the solar system. Given the distance of Gliese 581d from the star, this planet would be in the outer habitable zone. This world would be colder than Earth, but much warmer than Mars. The planet's semi-major axis is 0.2153 AU. However, th...