If someone asks you what planet is closest to Earth, you’ll probably blurt out Venus. That’s a perfectly normal thing to say, but it’s also wrong. Numerous websites and even NASA itself say Venus is our closest planetary neighbor. A new article in Physics Today lays out a more accurate way to determine which planets are closest together. It turns out the averages are highly counterintuitive. Mercury is the closest planet to Earth -- in fact, it’s the closest planet to every other planet.
It may not look like much, but this orangey brown puff of smoke high is the aftermath of the third largest meteor explosion to have impacted Earth in modern times. The huge meteor explosion hit Earth in December but was only spotted by researchers last week, and now we have visual evidence thanks to the camera of the geostationary Japanese Himawari-8 weather satellite.
A meteor caused a massive explosion over Earth last year, but nobody noticed until now. It is the second-largest recorded impact in the past century, after the meteor that exploded over the Russian region of Chelyabinsk in 2013. The giant fireball hit at 2350 GMT on 18 December over the Bering Sea, a part of the Pacific Ocean between Russia and Alaska.
NASA has some good news, the world is a greener place today than it was 20 years ago. What prompted the change? Well, it appears China and India can take the majority of the credit. In contrast to the perception of China and India's willingness to overexploit land, water and resources for economic gain, the countries are responsible for the largest greening of the planet in the past two decades. The two most populous countries have implemented ambitious tree planting programs and scaled up their implementation and technology around agriculture.
NOAA’S National Centers for Environmental Information has updated the World Magnetic Model to reflect the change. “Typically, a new and updated version of the WMM is released every five years. With the last release in 2015, the next version is scheduled for release at the end of 2019,” it explained, in a statement. “Due to unplanned variations in the Arctic region, scientists have released a new model to more accurately represent the change of the magnetic field between 2015 and now.”
Some 4.5 billion years ago, a Mars-sized rock is theorized to have collided with the proto-Earth. The collision is one of the only ways to create an Earth-Moon system with the properties we observe today. It also may have partially re-liquefied Earth’s surface, destroyed Chaotian property values, and created an atmosphere of plasma metal vapor around both our planet and the enormous cloud of angry debris that now surrounded it.
In his 1864 science fiction novel, Journey to the Center of the Earth, Jules Verne wrote: "Who in his wildest dreams could have imagined that, beneath the crust of our Earth, there could exist a real ocean ... a sea that has given shelter to species unknown?" Scientists have found that rocks beneath the seafloor are teeming with microbial life.
Geoengineering -- the deliberate effort to manipulate the Earth’s climate in an attempt to offset, delay, or slow global warming -- has slowly transformed from a pie-in-the-sky idea to a serious concept that may well be attempted one day. A wide variety of schemes have been proposed for how we might cool the Earth, but many of these would require the development of technologies far beyond our current capability.
In order to make accurate weather predictions, NOAA needs weather satellites in orbit to peer down at Earth. Until recently, the agency was making do with very old hardware from the 1990s, but it has since started launching the much improved GOES-R satellites. GOES-17 launched in March of this year, and it sent back a few images shortly after that.
If astrophysicist Jonathan McDowell's calculations are correct, the cosmic boundary where the laws of airspace suddenly give way to the laws of orbital space might be a lot closer than we think -- a full 12 miles closer than previous estimates suggest.