Humanity first left the solar system in 2012 when the Voyager 1 probe passed into interstellar space decades after leaving the planets behind. Now, there’s a second spacecraft beyond the limits of our solar system : Voyager 2. Luckily, Voyager 2’s instruments are in somewhat better shape than Voyager 1’s, so scientists were able to observe the transition from the heliosphere, which is dominated by the sun, to the interstellar medium (ISM).
Both Voyager probes launched in 1977, with Voyager 2 heading into space a few weeks before Voyager 1. The two probes are physically identical, but they took different paths through the solar system. They took advantage of the “Grand Tour,” an alignment of the planets that occurs only once every 175 years. Voyager 1 visited and got gravity assists from Jupiter and Saturn before heading off toward the edge of the solar system. Voyager 2 swung past Jupter, Saturn, Neptune, and Uranus. It made its last planetary observation of Uranus in 1989, almost a decade after Voyager 1 had started its long march toward the edge of the solar system.
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What's Up: Skywatching Tips from NASA – NASA Solar System Exploration
On November 11 we're in for a rare treat, as the innermost planet, Mercury, passes directly in front of the Sun for a few hours.
This event is called a transit, and for Mercury they happen only about 13 times in a century. (Transits of Venus are even more rare.)
The event will last about five and a half hours, during which Mercury's path will take it right across the middle of the Sun's disk. For observers in the Eastern U.S., the transit begins after sunrise, meaning you'll be able to view the entire thing. For the central and western U.S., the transit begins before sunrise, but there's enough time left as the Sun climbs up the sky for you to catch a glimpse before Mercury makes its exit.
Now remember, you should never look directly at the Sun without proper protection, as it can permanently damage your eyes. If you have a pair eclipse shades, those are okay for viewing the Sun, but Mercury is so small in comparison that it can be next to impossible to see a transit without magnification.
Asteroid Hygiea May Be the Smallest Dwarf Planet in the Solar System | Space
The asteroid Hygiea may qualify as a dwarf planet — and it could steal the title of the smallest dwarf planet in the solar system!
Astronomers have captured high-resolution imagery of Hygiea, the fourth largest rock in the Asteroid Belt . And low and behold, Hygiea is spherical in shape. That's a pretty important dwarf-planet marker, and the only one Hygiea was missing until now.
Asteroids boast a variety of shapes, but the rounded shape of dwarf planets shows that they had enough mass for its own gravity to pull it into this round shape. Hygiea already met the other requirements for dwarf-planet classification since it orbits the sun, is not a moon orbiting another planet and has not cleared other objects out of its own orbit.
Video: Asteroid Hygiea May Be Smallest Dwarf Planet in Our Solar System
Related: Meet the Solar System's Dwarf Planets
NASA Probe Provides Insight on Solar System's Border with Interstellar Space | Voice of
The journey of NASA's dauntless Voyager 2 spacecraft through our solar system's farthest reaches has given scientists new insight into a poorly understood distant frontier: the unexpectedly distinct boundary marking where the sun's energetic influence ends and interstellar space begins.
The U.S. space agency previously announced that Voyager 2, the second human-made object ever to depart the solar system following its twin Voyager 1, had zipped into interstellar space on Nov. 5, 2018, at a point more than 11 billion miles (17.7 billion km) from the sun. Several research papers published Monday provided scientific details of that crossing.
Both Voyager 1 and Voyager 2 were launched in 1977, designed for five-year missions. Voyager 1 left the solar system at a different location in 2012. Both are now traversing the Milky Way galaxy's interstellar medium, a chillier region filling the vast expanses between the galaxy's stars and planetary systems.
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Fast Times in the Early Solar System | Planetary News
Calcium-aluminum-rich inclusions, CAIs, are light-colored masses in carbonaceous chondrite meteorites — they are the first formed solids in the solar system. Being so old, they provide a unique view into processes early in our solar system, including when and how its dust coagulated to form larger objects (like CAIs) and eventually planets. A team of scientists, led by M. C. Liu of the University of California Los Angeles, determined the ages of some microscopic CAIs from a pristine carbonaceous chondrite to peer back into the early days of our solar system and everything in it. Using a precise radio-isotope chronometer, they found that dust grains stuck to each other to form CAIs on (astronomically) short timescales of 50,000 to 100,000 years. This suggests that dust coagulates very rapidly.
NASA's Voyager probes solar system border | 7NEWS.com.au
The journey of NASA's dauntless Voyager 2 spacecraft through our solar system's farthest reaches has given scientists new insight into a poorly understood distant frontier: the unexpectedly distinct boundary marking where the sun's energetic influence ends and interstellar space begins.
The US space agency previously announced that Voyager 2, the second human-made object ever to depart the solar system following its twin Voyager 1, had zipped into interstellar space on November 5, 2018 at a point more than 17.7 billion km from the sun.
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Both Voyager 1 and Voyager 2 were launched in 1977, designed for five-year missions. Voyager 1 left the solar system at a different location in 2012.
Both are now traversing the Milky Way galaxy's interstellar medium, a chillier region filling the vast expanses between the galaxy's stars and planetary systems.
OffWorld's Smart Robots Could Swarm Solar System to Help Astronauts and Settlers | Space
WASHINGTON — Future lunar explorers could have smart robots ready to help them thanks to OffWorld, a company that plans a fleet of industrial machines for destinations all over the solar system.
The California-based company already has some undisclosed Fortune 500 companies paying it to deploy robots on Earth for applications such as mining. And while the tech is all early stage, OffWorld said it plans to go a lot further.
While it's still too early to tell when the robots would leave our planet, OffWorld CEO Jim Keravala told Space.com at the International Astronautical Congress that he would be pleased if future robotic generations could assist NASA's astronauts when they land on the surface of the moon, a mission scheduled for 2024.
Related: Moon VIPER: NASA Wants to Send a Water-Sniffing Rover to the Lunar South Pole in 2022
How Hot is the Sun? | Interesting Facts About the Sun
4.5 billion years ago, in the Orion Spur of the Milky Way galaxy, a swirling cloud of gas and dust collapsed under the weight of its own gravity. This so-called solar nebula spun faster and faster, and—as it eventually flattened out—most of that material drew toward the center, giving birth to our home star, the sun.
At its equator, the sun rotates approximately every 27 days. But at its poles, it rotates roughly every 36 days. Sounds strange, right? Well, the sun isn’t made of solid matter like Earth is, so that means that different parts of the star rotate at different times.
The atomic weight of the sun is composed of 92.1 percent hydrogen and 7.8 percent helium, with traces of carbon and nitrogen. (By mass, it's more like 70.6 percent hydrogen and 27.4 percent helium. It has six layers: Its core, the innermost layer, reaches temperatures of up to 27 million degrees. This is where the sun gets all of its energy. Within the core, hydrogen atoms join together in a thermonuclear reaction to create helium, according to NASA.
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