Why not recycled concrete?

From paper towels to cups to plastic bottles, products made from recycled materials permeate our lives. One notable exception is building materials. Why can’t we recycle concrete from our deteriorating infrastructure for use as material in new buildings and bridges? It’s a question that a team of researchers is examining. —> Read More

Gravitational Waves and How They Distort Space

Gravitational waves distort space in a rhythmic fashion. These simple animations show how.

It’s official: on February 11, 10:30 EST, there will be a big press conference about gravitational waves by the people running the gravitational wave detector LIGO. It’s a fair bet that they will announce the first direct detection of gravitational waves, predicted by Albert Einstein 100 years ago. If all goes as the scientists hope, this will be the kick-off for an era of gravitational wave astronomy: for learning about some of the most extreme and violent events in the cosmos by measuring the tiny ripples of space distortions that emanate from them.Time to brush up on your gravitational wave knowledge, if you haven’t already done so! Here’s a visualization to help you – and we’ll go step by step to see what it means: Visualization of a simple gravitational wave. Gravitational waves distort space in a rhythmic fashion.

Einstein’s distorted spacetime

In the words of the eminent relativist John Wheeler, Einstein’s theory of general relativity can be summarized in two statements: Matter tells space and time how to curve. And (curved) space and time tell matter how to move. (Here is a slightly longer version on Einstein Online.)Einstein published the final form of his theory in November 1915. By spring 1916, he had realized another consequence of distorting space and time: general relativity allows for gravitational waves, rhythmic distortions which propagate through space at the speed of light.For quite some time, physicists weren’t sure whether these gravitational waves were real or a mathematical artifact within Einstein’s theory. (For more about this controversy, see Daniel Kennefick’s book “Traveling at the Speed of Thought and this article.) But since the 1980s, there has been indirect evidence for these waves (which earned its discoverers a Nobel prize, no less, in 1993).Gravitational waves are —> Read More

All Primary Mirrors Fully Installed on NASA’s James Webb Space Telescope

All 18 primary mirrors of NASA's James Webb Space Telescope are seen fully installed on the backplane structure by technicians using a robotic arm (center) inside the massive clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland.  Credit: Ken Kremer/kenkremer.com

NASA GODDARD SPACE FLIGHT CENTER, MD – All 18 of the primary mirrors have been fully installed onto the flight structure of what will become the biggest and most powerful space telescope ever built by humankind – NASA’s James Webb Space Telescope (JWST).Completion of the huge and complex primary mirror marks a historic milestone and a banner start to 2016 for JWST, commencing the final assembly phase of the colossal observatory that will revolutionize our understanding of the cosmos and our place it in.After JWST launches in slightly less than three years time, the gargantuan observatory will significantly exceed the light gathering power of the currently most powerful space telescope ever sent to space – NASA’s Hubble!Indeed JWST is the scientific successor to NASA’s 25 year old Hubble Space Telescope.Technicians working inside the massive clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, have been toiling around the clock 24/7 to fully install all 18 primary mirror segments onto the mirror holding backplane structure. This author witnessed ongoing work in progress during installation of the last of the primary mirrors.The engineers and scientists kept up the pace of their assembly work over the Christmas holidays and also during January’s record breaking monster Snowzilla storm, that dumped two feet or more of snow across the Eastern US from Washington DC to New York City and temporarily shut down virtually all travel.The team used a specialized robotic arm functioning like a claw to meticulously latch on to, maneuver and attach each of the 18 primary mirrors onto the telescope structure.Each of the 18 hexagonal-shaped primary mirror segments measures just over 4.2 feet (1.3 meters) across and weighs approximately 88 pounds (40 kilograms). They are about the size of a coffee table.In space, the folded —> Read More

Cockroach inspires robot that squeezes through cracks

Ever wonder how roaches are able to get into anything, no matter how tight the seams? Biologists have now shown that the American cockroach can flatten its body to one-fifth normal running height to squeeze through cracks as small as two stacked pennies, and can run at high speed when flattened by half. These features were reproduced in a squishy robot that can run even when flattened: ideal for search and rescue. —> Read More

1 2 3 5,414