Fireball created by the Hayabusa2 re-entry capsule as it passes through the Earth's atmosphere towards the ground (JAXA). In the mission control room in Japan, all eyes were fixed on one of the large screens that ran along the far wall. The display showed the night sky, with stars twinkling in the blackness. We were …
Continue reading "Japan’s Hayabusa2 Mission Returns to Earth"
When our sun was young, it was significantly less luminous and sent out significantly less warming energy than it does now. Scientists estimate that 4 million years ago, when the sun and our solar system were 500 million years old, the energy that the sun produced and dispersed was about 75 percent of what it …
When describing exoplanets that are potentially promising candidates for life, scientists often use the terminology of the "habitable zone." This is a description of planets in orbit where temperatures, as predicted by the distance from the host star, are not too cold for liquid water to exist on a planetary surface and also not to …
Continue reading "How Radioactive Elements May Make Planets Suitable or Hostile to Life"
What started as a stunning announcement that the chemical phosphine -- a known byproduct of life -- had been found in the clouds of Venus and could signal the presence of some lifeform has now been strongly critiqued by a number of groups of scientists. As a result, there is growing doubt that the finding, …
Long before there was an Earth, asteroids large and small were orbiting our young sun. Among them was one far enough out from the sun to contain water ice, as well as organic compounds with lots of carbon. In its five billion years or so as an object, the asteroid was hit and broken apart …
As we grow more ambitious in our desires to see further and more precisely in space, the need for larger and larger telescope mirrors becomes inevitable. Only with collection of significantly more photons by a super large mirror can the the quality of the "seeing" significantly improve. The largest mirror in space now is the …
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Nightside of Venus captured with the IR2 (infrared) camera on JAXA's Akatsuki climate orbiter (JAXA). On September 14 at 3pm GMT, an embargo lifted on a research paper reporting evidence for biological activity on Venus. Speculation about the discovery had been spreading rapidly through social media for several days, proving that scientists are incapable of …
One of the enduring puzzles of our planet is why it is so wet. Since Earth formed relatively close to the sun, planetary scientists have generally held that any of the water in the building blocks of early-forming Earth was baked out and so was unavailable to make oceans or our atmosphere. That led to …
Continue reading "An “Elegant” New Theory on How Earth Became a Wet Planet"
Our solar system has but one planet orbiting in what is commonly known as the habitable zone -- at a distance from the host star where water could be liquid at times rather than always ice or gas. That planet, of course, is Earth. But from a theoretical, dynamical perspective, does this always have to …
Continue reading "How Many Habitable Zone Planets Can Orbit a Host Star?"
For space scientists of all stripes, few goals are as crucial as bringing pieces of Mars, of asteroids, of other planets and moons back to Earth for the kind of intensive study only possible here. Space missions can, and have, told us many truths about the solar system, but having a piece of Mars …
Many Worlds 