To tackle this puzzle, Malhotra and colleagues considered a less-examined scenario: that a visiting star-size object tweaked these planets' paths around 4 billion years ago. Related: Giant 'kidney ...

We study the ~4.5 billion year history of the terrestrial planets of our solar system, from the stellar synthesis of the elements of which they comprise through their accretion and re-organisation by ...

Seven planets will line up for a rare "planetary parade" today (Feb. 28) and you can watch it live online, beginning at 12:00 p.m. ET (1700 GMT).

Terrestrial biomes are distinguished primarily ... coniferous forests, and tundra (Figure 4). Tropical forests are found in areas centered on the equator (Figure 4). Central and South America ...

This water, now over 4.5 billion years old ... In a way, the disk "waters" the terrestrial planets: Mars, Earth, Venus and Mercury. Most of this water capture occurred 20 to 30 million years ...

Most terrestrial planets have atmospheres, but the conditions on their surfaces would not allow humans to survive there. Venus is the hottest planet in our solar system (despite being further from ...