Tag: planets

Hadean Oceans

Oceans formed far more quickly than expected:

The Hadean eon, following the global-scale melting of the mantle, is expected to be a dynamic period, during which Earth experienced vastly different conditions. Geologic records, however, suggest that the surface environment of Earth was already similar to the present by the middle of the Hadean. Under what conditions a harsh surface environment could turn into a habitable one remains uncertain. Here we show that a hydrated mantle with small-scale chemical heterogeneity, created as a result of magma ocean solidification, is the key to ocean formation, the onset of plate tectonics and the rapid removal of greenhouse gases, which are all essential to create a habitable environment on terrestrial planets. When the mantle is wet and dominated by high-magnesium pyroxenites, the removal of carbon dioxide from the atmosphere is expected to be more than ten times faster than the case of a pyrolytic homogeneous mantle and could be completed within  160 ma. Such a chemically heterogeneous mantle would also produce oceanic crust rich in olivine, which is reactive with ocean water and promotes serpentinization. Therefore, conditions similar to the Lost City hydrothermal field may have existed globally in the Hadean seafloor.

ML planet Hunting

Using a dataset of more than 15K labeled Kepler signals, we created a TensorFlow model to distinguish planets from non-planets. To do this, it had to recognize patterns caused by actual planets, versus patterns caused by other objects like starspots and binary stars. When we tested our model on signals it had never seen before, it correctly identified which signals were planets and which signals were not planets 96% of the time. So we knew it worked!

Private exoplanet hunting

Unlike the Kepler Space Telescope—which monitored 100k stars and looked for slight dimming to determine when planets passed in front of their parent stars—Project Blue will use high-contrast imaging. Technical studies have shown that, with an advanced coronagraph to block light from the stars and data processing techniques, such a telescope could reject light from the 2 stars at a rate of 10B to 1. This is sufficient to allow direct imaging of a planet with observations made over the course of several years. Put another way, such an observation system is akin to detecting a firefly next to a lighthouse 16km away.

The proposed telescope should be able to resolve a world that is 0.5 to 1.5 times of the size of Earth and orbiting within the host star’s “habitable zone,” where water theoretically could exist on the surface. Based on Kepler’s data, with 2 Sun-like stars to search around, the odds of at least 1 terrestrial planet in the habitable zone is 80%.