Rocky New Planets Prove Planet-Hunting Technique and Other Stories

Recreational Fishing Threatens Marine Stocks

Weekend fishing trips may be contributing to one-quarter of the catch of threatened marine fish, a new study finds. U.S. Fisheries managers previously thought that recreational fishers caught just 2 percent of all fish taken from the sea. They based this conclusion on an online database compiled by the National Marine Fisheries Service.

But a rise in the popularity of angling, combined with gaps in the data, led Felicia Coleman of Florida State University and her colleagues to take a second look at the impact of part-time anglers. With the addition of regional information, their results, published in the journal Science, implicate recreational fishing in 4 percent of the total marine catch. For already overfished species, however, the number is more like 23 percent. And for specialty fish such as red drum, popular in Cajun cuisine, recreational fishing is responsible for nearly 95 percent of the catch.

Coleman says the results suggest tighter restrictions are necessary for sportfishing, which is typically regulated only by quotas. To counter the free-fall in fish stocks, scientists propose establishing marine reserves off-limits to both commercial and recreational fishing. 

White House Report: Humans Caused Global Warming

A new report from the Bush administration has found that humans are responsible for the last 50 years of global warming. The findings, delivered to Congress, contradict the administration's previous stance that there was no evidence for a link between human activities and global warming. The report synthesizes decades of federal research on climate.

The National Center for Atmospheric Research in Boulder, Colorado, attempted to reproduce the last century of observed climate change using sophisticated climate models. They found that natural Sun cycle shifts were sufficient to produce the warming observed from 1900 to 1950. However, they had to add in greenhouse gas contributions from industry and automobiles to obtain the sharp temperature rises noted in the decades since then.

The report also forecast warming effects on food production. It predicts grasslands will be less digestible for cattle and weeds will benefit more from the extra carbon dioxide than crops, lowering agricultural yields. These findings were based on the results of experiments on Colorado fields exposed to twice the current levels of carbon dioxide. 

Rocky New Planets Prove Planet-Hunting Technique

A slew of small planets has been discovered lately, highlighting the fevered pace at which astronomers are combing the universe for places conducive to life.

Two tiny Neptune-sized exoplanets — worlds which orbit stars other than our Sun — were announced by American teams this week. Telescopes in Hawaii and Texas were able to measure the gravitational wobble the planets induced on their stars. These exoplanets represent a class of celestial bodies 14 to 18 times the mass of Earth, whereas previous discoveries of gigantic gaseous bodies were about 300 times larger — around the size of Jupiter.

Astronomers believe the planets formed far from their suns and migrated inward to their present positions. If this is true, the planets may well be rocky like Earth. The findings will be detailed in an upcoming issue of the Astrophysical Journal. The European Space Agency has also been busy planet-hunting and announced a similar planetary find last week. 

A Practical, Accurate Atomic Clock

The world's smallest atomic clock is on its way into cell phones and GPS units near you. Normal quartz clocks can lose up to two seconds per week, but atomic tickers stay on track for centuries because their tocks are based on the vibration of atoms.

Cesium, for example, jostles exactly 9.2 billion times per second, so John Kitching of the National Institute of Standards and Technology fashioned a tiny chamber capable of holding a billion cesium atoms to make a clock.

The new timepiece, the size of a grain of rice, is a major space-saver; some atomic clocks, while more accurate, measure up to two meters high. The new invention runs off an AA battery and loses just one second every 300 years. It should hit the market in a couple of years, says Kitching in Applied Physics Letters. 

Related Links

Recreational Fishing Threatens Marine Stocks: National Geographic / Scientific American
White House Report: Humans Caused Global Warming: New York Times / CNN (Reuters) 
Rocky New Planets Prove Planet-Hunting Technique: BBC / Yahoo Daily News (Associated Press) / New Scientist
A Practical, Accurate Atomic Clock: Nature News / Scientific American 

Source: Top Stories