math test: a farmer plants 7 crops of tomatoes and 3 crops of carrots what is the probablity his moms name is leslie
history test: the american civil war ended in 1865, explain how this had a defining role in the extinction of dinosaurs
literature test: explain what the author meant by, "the apple was as red as an apple"
physics tests: The aliens ate 3.4 doughnuts. Their crumbs fell to the Earth because of gravity. Calculate how many penguins are eating pancakes at the speed of light.
‘History shows us that simply being curious about the universe and allowing ourselves to explore it is by far the best way to make discoveries which change everybody’s lives.’
Dragon grappled by Canadarm2
With clouds over Earth forming a backdrop, the SpaceX Dragon commercial cargo craft is grappled by the Canadarm2 robotic arm at the International Space Station. Expedition 31 Flight Engineers Don Pettit and Andre Kuipers grappled Dragon at 9:56 a.m. (EDT) and used the robotic arm to berth Dragon to the Earth-facing side of the station’s Harmony node at 12:02 p.m. May 25, 2012.
Stellar Archaeology Traces Milky Way’s History
Unfortunately, stars don’t have birth certificates. So, astronomers have a tough time figuring out their ages. Knowing a star’s age is critical for understanding how our Milky Way galaxy built itself up over billions of years from smaller galaxies. Astronomers from the Space Telescope Science Institute and The Johns Hopkins University’s Center for Astrophysical Sciences have found the next best thing to a star’s birth certificate.
Using a new technique, Kalirai probed the burned-out relics of Sun-like stars, called white dwarfs, in the inner region of our Milky Way galaxy’s halo. The halo is a spherical cloud of stars surrounding our galaxy’s disk. Those stars are 11.5 billion years old, younger than the first generation of Milky Way stars.
They formed more than 2 billion years after the birth of the universe 13.7 billion years ago. Previous age estimates, based on analyzing normal stars in the inner halo, ranged from 10 billion to 14 billion years. The new study reinforces the emerging view that our galaxy’s halo is composed of a layer-cake structure that formed in stages over billions of years.
Above: This illustration shows the Milky Way galaxy’s inner and outer halos. A halo is a spherical cloud of stars surrounding a galaxy. Astronomers have proposed that the Milky Way’s halo is composed of two populations of stars. The age of the stars in the inner halo is 11.5 billion years old. The measurements suggest the inner-halo stars are younger than the outer-halo population, some of which could be 13.5 billion years old.
