Scientists have recently found something entirely new -- a galaxy with the same mass as the Milky Way but with only 1 percent of our galaxy's star power. About 99.99 percent of this other galaxy is made up of dark matter, and scientists believe it may be one of many.
The galaxy Dragonfly 44, is said to be 300 million light years away. If scientists can track down a similar galaxy closer to home, however, they may be able to use it to make the first direct detection of dark matter.
Dark matter is the name given to a mysterious form of matter that we know must be there. Without something adding to the mass of the universe, things would tear apart. The laws of physics require some unknown, unseen kind of something to hold the universe together (while dark energy pushes it farther and farther apart). All we really know about dark matter is that it barely interacts with anything, including its own ilk.
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Scientists' investigations of the closest star, Proxima Centauri, has show that there is an Earth-sized planet orbiting about it. What is more, this rocky globe is moving in a zone that would make liquid water on its surface a possibility.
Proxima is 40 trillion km away but the discovery of a planet potentially favourable to life in our cosmic neighbourhood is likely to fire the imagination.
The distance between the star and its planet is considerably smaller than Earth's separation from the Sun (149 million km). But Proxima Centauri is what is termed a red dwarf star. It is much reduced in size and dimmer compared with our Sun, and so a planet can be nearer and still enjoy conditions that are potentially as benign as those on Earth.
Scientists have found that this planet is at 5% of the Earth's distance from the Sun. However, Proxima is 1,000 times fainter than the Sun. So the flux - the energy - reaching Proxima b is about 70% of what the Earth receives. It's like taking Earth a bit further away, but it's comparable.
Whether the temperatures on Proxima b are favourable for life to exist is going to depend on the presence of an atmosphere. An envelope of greenhouse gases would warm surface conditions and provide sufficient pressure to keep water - essential for biology - in a liquid state.
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Two NASA astronauts successfully installed a new parking spot at the International Space Station, marking a key step toward accommodating new commercial space taxis that arrive at the orbiting lab.
Jeff Williams, commander of Expedition 48, and flight engineer Kate Rubins ventured outside of the space station, one minute ahead of schedule. The spacewalk came to an early end at 2:02 p.m. EDT (1802 GMT) due to a minor communication problem.
"The view is phenomenal," Rubins said, as she exited the space station's Quest airlock. Today's spacewalk marked a first for Rubins and the fourth of Williams' career.
The installation of the IDA means the space station will be able to accommodate various space taxis, including SpaceX and Boeing vehicles. Before now, only Russian vehicles were able to dock with space station.
Due to broken communication with Williams' right ear piece, additional minor "go ahead" tasks were called-off and the two astronauts headed back to the space station's airlock.
On Sept. 1, Williams and Rubins are likely to perform a second 6.5-hour spacewalk to retract one of the station's thermal radiators, among other tasks. Williams will return home Sept. 6 with Russian cosmonauts Oleg Skripochka and Alexey Ovchinin. Williams is set to surpass Scott Kelly's record for the most total cumulative time spent in space by an American, with a total of 534 days.
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A team of Japanese, South African, and Italian astronomers recently found that there is a massive region around the center of the Milky Way that is devoid of young stars.
The Milky Way is a spiral galaxy, and the Sun is almost 26,000 light-years from the center in one of its spiral arms. Measuring the distribution of stars within the galaxy is very important in understanding how our galaxy formed and evolved.
Young, pulsating stars called Cepheid Variable stars, or Cepheids for short, are the perfect candidate for this. They are between 10 and 300 million years old, younger than our Sun at 4.6 billion years old, and pulsate in their brightness in a repeating cycle. As this pulsation time is related to its luminosity, astronomers can monitor them to determine their actual brightness; after comparing this with the brightness as seen from Earth, a distance can be determined.
Finding these stars is difficult as the center of the galaxy is full of interstellar dust that obscures the light and hides many stars from view. Using near-infrared observations from the South African Large Telescope (SALT), the team was able to see past the dust; to their surprise they found hardly and Cepheids around a region about 1,000 light-years wide from the core of the galaxy.
The recent findings suggest that the extreme inner disk has virtually no young stars and that no significant amount of star formation has occurred in this area for hundreds of millions of years. The chemical makeup and movement of the Cepheid Variable stars are guiding the team in understanding the formation of the galaxy.
Mostly Cepheids have been used to measure distances of objects in far off in the universe, but this new study shows that the same technique can be used in revealing information a lot closer to home.
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In a few weeks, scientists could be one step closer to understanding fundamental questions about the origins of our planet and the human race; from an asteroid that could threaten to destroy us.
The OSIRIS-REx Mission, headed by NASA and the University of Arizona, plan to launch an unmanned spacecraft on September 8 in the efforts to reach Bennu, a large near-Earth asteroid in August 2018.
The spacecraft will survey Bennu until a small vacuum-like device is capable of hovering above the asteroid and sucking up somewhere between 60 and and 400 grams of "gravel and soil" to bring back to Earth in the year 2023, according to Dante Lauretta, a professor of planetary science and cosmochemistry at the University of Arizona's Lunar and Planetary Laboratory, and the principal investigator on the OSIRIS-REx mission.
As a near-Earth asteroid, Bennu once existed in what he described as a main asteroid belt, located between Mars and Jupiter. There, it was likely dislodged by a gravitational pull towards Saturn, sending it closer to us. The asteroid could indeed strike Earth, and cause tremendous destruction.
Bennu has a one in 2,700 chance of hitting Earth, and such an event wouldn't take place for 150 years. People living in the year 2135 would know whether the asteroid posed a threat to hit Earth. Bennu would enter a "keyhole" located between the Earth and the moon that would send it in the direction of Earth.
A one in 2,700 chance isn't too insignificant. But by the time it would strike, we would likely have the technology to destroy Bennu.
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