Mars is no longer what it was. This NASA 3D recreation shows how scientists believe the red planet was 4 billion years ago, much more like Earth than today. In fact, researchers recently discovered, Mars had an oxygen-rich atmosphere precisely 4 billion years ago, long before atmospheric oxygen emerged about 2.5 billion years ago.
Video: The 4 billion year evolution of Mars in 2 minutes
Slaves and Disabled: Forced Medical Test Volunteers
The main problem to carry out medical research is to have willing volunteers for it. And if they come out for free, much better. This is the story of unethical behavior in medical research.
How are lightning created?
Summer is synonymous with sun, but also with storms. Who has not contemplated one from the protection that the home gives that electrical display that is lightning?
How global warming will affect astronomy
Astronomical observations around the world will worsen in quality as a result of climate change, according to a new study.
New images of Saturn's rings in stunning detail
New images of Saturn's rings in stunning detail
NASA discovers more than 50 areas that emit exorbitant levels of greenhouse gases
NASA's 'EMIT' spectrometer locates has targeted Central Asia, the Middle East and the US among others.