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Phenomenally durable crystals called zircons are used to date some of the earliest and most dramatic cataclysms of the solar system. One is the super-duty collision that ejected material from Earth to form the moon roughly 50 million years after Earth formed. Another is the late heavy bombardment, a wave of impacts that may have created hellish surface conditions on the young Earth, about 4 billion years ago.

Both events are widely accepted but unproven, so geoscientists are eager for more details and better dates. Many of those dates come from zircons retrieved from the moon during NASA's Apollo voyages in the 1970s.

Treinta y uno por ciento de las especies de cactus están amenazadas con la extinción, según la primera evaluación integral, global del grupo de especies de la Unión Internacional para la Conservación de la Naturaleza (UICN, International Union for Conservation of Nature) y asociados, publicado en la revista Plantas Naturales (Nature Plants).

Tattoos really are more than skin deep—and that raises questions about their safety.

Many people enjoy the aesthetic beauty of tattoos. But the brightly colored inks that make tattoos so vibrant and striking also carry health concerns, report authors of a new paper related to tattoo safety.

According to the Pew Research Center, 45 million Americans have at least one tattoo; roughly $1.65 billion is spent on tattoos each year in the U.S.

Hacer predicciones sobre la variabilidad del clima a menudo significa voltear al pasado para encontrar tendencias. Ahora los investigadores “paleo-climáticos” de la Universidad de Missouri (UM) han encontrado pistas en el lecho de una roca expuesta junto a una autopista de Alabama, que podría ayudar a pronosticar la variabilidad del clima. En su estudio, los investigadores verificaron evidencia de que el dióxido de carbono se redujo significativamente al final del Período Ordovícico, hace 450 millones de años, precediendo a una edad de hielo y una extinción masiva. Estos resultados ayudarán a los climatólogos a predecir mejor los futuros cambios ambientales.

This week, EPA Administrator Gina McCarthy joined private and public sector leaders for a second annual White House roundtable discussion about the progress made and new steps taken to curb emissions of hydrofluorocarbons (HFCs), potent greenhouse gases used in refrigeration and air conditioning. Administrator McCarthy announced several new actions the agency will take to help support a smooth transition to climate-friendly alternatives to HFCs.

"EPA is working closely with industry leaders to reduce greenhouse gas emissions, transition to climate-friendly refrigerants, and deploy advanced refrigeration technologies,” said EPA Administrator Gina McCarthy. “The powerful combination of EPA’s regulatory actions and innovations emerging from the private sector have put our country on track to significantly cut HFC use and deliver on the goals of the President’s Climate Action Plan.”