dilluns, 3 de setembre del 2018

Here's the closest image yet of potentially hazardous asteroid Bennu

The OSIRIS-REx spacecraft obtained the first images of its target asteroid Bennu from a distance of 1.4 million miles (2.2 million km) on August 17.
NASA's OSIRIS-REx spacecraft is now closer than we've ever been to the potentially hazardous asteroid 101955 Bennu, and the space agency is preparing to intercept the space rock and bring a chunk of it home for study. 

This isn't just a random hunk of cosmic debris that NASA chose for this mission.
As OSIRIS-REx principal investigator Dante Lauretta told reporters on a conference call Friday, Bennu "has a not-insignificant probability of impacting the Earth." (OSIRIS-REx stands for Origins, Spectral Interpretation, Resource Identification, Security - Regolith Explorer.)
Fortunately, when talking about space objects, "not insignificant" can still mean "not worth losing sleep over anytime soon." Scientists estimate that Bennu has a 1 in 2,700 chance of hitting Earth sometime between 2175 and 2196.
OSIRIS-REx launched in September 2016 and came close enough to capture its first images of its destination last week, which were just released during this Friday's press call. The spacecraft pointed its cameras at the asteroid on Aug. 17 and snapped the closest photos ever of Bennu from a distance of 1.4 million miles (2.2 million km).
Between now and December, the spacecraft will move ever closer to the asteroid, surveying the area and eventually mapping the surface and spin of Bennu. This is all in preparation for a five-second high-five of the asteroid with a specially designed robotic arm that will take a sample to bring home for analysis. 
The OSIRIS-REx team hopes the mission will yield all kinds of useful data and potential insights into the formation of the solar system, the origins of life and resources locked up in asteroids that might be tapped by humanity in the future. 
But perhaps most important from an existential perspective is the opportunity to learn enough to head off possible future collisions. 
"We want to understand all of the forces that influence its orbital trajectory," said Lauretta, adding that the mission also provides the opportunity to verify spectral data on asteroids collected from various telescopes that never have a chance to get nearly so close to the real thing.  
He also hopes the mission may help in measuring the effect of sunlight on the orbit of a small asteroid, known as the Yarkovsky effect, which could prove useful in nudging potentially dangerous asteroids onto new trajectories involving less planet-smashing.
Get ready to become a lot more familiar with Bennu as OSIRIS-REx draws ever closer in the coming months, and then spends 2019 orbiting the asteroid as close as just 1.5 km (1 mile) above its surface. Finally, the spacecraft will move in for a minor planet pick-pocketing in 2020. 

L'atac nord-americà de Doolittle contra el Japó va canviar el corrent de la Segona Guerra Mundial

Fa 80 anys: el Doolittle Raid va marcar el dia que sabíem que podríem guanyar la Segona Guerra Mundial. Com a patriòtic nord-americà, durant...