THIS SITE IS UPDATED OFTEN TO HELP YOU FIND YOUR WAY AROUND THE COSMOS.
This boundary, called the heliopause, is where the hot solar wind meets the cold, dense interstellar medium. Voyager 2’s twin spacecraft, Voyager 1, crossed this boundary in 2012, but Voyager 2 carries a working instrument that will provide first-of-its-kind observations of the nature of this gateway into interstellar space. Voyager 2 now is slightly more than 11 billion miles (18 billion km) from Earth. Mission operators still can communicate with Voyager 2 as it enters this new phase of its journey, but information – moving at the speed of light – takes about 16.5 hours to travel from the spacecraft to Earth. By comparison, light traveling from the sun takes about eight minutes to reach Earth.Together, the two Voyagers provide a detailed glimpse of how our heliosphere interacts with the constant interstellar wind flowing from beyond. While the probes have left the heliosphere, Voyager 1 and Voyager 2 have not yet left the solar system, and won’t be leaving anytime soon. The boundary of the solar system is considered to be beyond the outer edge of the Oort Cloud, a collection of small objects that are still under the influence of the sun’s gravity. The width of the Oort Cloud is not known precisely, but it is estimated to begin at about 1,000 astronomical units (AU) from the sun and to extend to about 100,000 AU (1 AU is the distance from the sun to Earth). It will take about 300 years for Voyager 2 to reach the inner edge of the Oort Cloud and possibly 30,000 years to fly beyond it. Voyager 2 launched in 1977, 16 days before Voyager 1, and both have traveled well beyond their original destinations. The spacecraft were built to last five years and conduct close-up studies of Jupiter and Saturn. However, as the mission continued, additional flybys of the two outermost giant planets, Uranus and Neptune, proved possible. As the spacecraft flew across the solar system, remote-control reprogramming was used to give Voyagers greater capabilities than they possessed when they left Earth. Their two-planet mission became a four-planet mission. Their five-year lifespans have stretched to 41 years, making Voyager 2 NASA’s longest running mission. Each spacecraft carries a Golden Record of Earth sounds, pictures and messages. Since the spacecraft could last billions of years, these circular time capsules could one day be the only traces of human civilization.
The Pleiades star cluster – also known as the Seven Sisters or M45 – is visible from virtually every part of the globe. It can be seen from as far north as the North Pole, and farther south than the southernmost tip of South America. It looks like a tiny misty dipper of stars. If you’re familiar with the famous constellation Orion, it can help you be sure you’ve found the Pleiades. See the three stars in a row in Orion? That’s Orion’s Belt. Draw a line through these stars to the V-shaped pattern of stars with a bright star in its midst. The V-shaped pattern is the Face of Taurus the Bull. The bright star in the V – called Aldebaran – depicts the Bull’s Eye. A bit past Aldebaran, you’ll see the Pleiades cluster, which marks the Bull’s Shoulder.
Have you heard about comet 46P/Wirtanen? It’s approaching the inner solar system, due to pass closest to our sun and Earth in December 2018. Comet Wirtanen is the brightest comet in the night sky now, although that doesn’t mean you can see it with the eye alone. In fact, it’s visible now only to astronomers with telescopes. But – in December 2018 – comet Wirtanen might be visible to the unaided eye, at least from dark skies. Closest approach to the sun will be December 12, 2018, and closest approach to Earth is just a few days later, on December 16. According to astronomers at the University of Maryland, this passage of comet Wirtanen near the Earth (near by comet standards, that is) will be the 10th closest approach of a comet in modern times. At its closest to us, the comet will be about 30 times the moon’s distance (7.1 million miles, or 11.5 million km).
Although several dozen minor galaxies lie closer to our Milky Way, the Andromeda galaxy is the closest large spiral galaxy to ours. Excluding the Large and Small Magellanic Clouds, which can’t be seen from northerly latitudes, the Andromeda galaxy – also known as M31 – is the brightest galaxy you can see. At 2.5 million light-years, it’s also the most distant thing visible to your unaided eye. To the eye, this galaxy appears as a smudge of light larger than a full moon.
It’s that magical time of year again, when the solar system’s favorite planet – Saturn – is well placed for viewing in our sky. Shining with a distinct golden color, Saturn is a lovely object to view with the eye alone. Binoculars will enhance its color … but to see Saturn’s rings you need a small telescope. And we do mean small. Veteran observer Alan MacRobert at SkyandTelescope.com has written: The rings of Saturn should be visible in even the smallest telescope at 25x [magnified by 25 times]. A good 3-inch scope at 50x [magnified by 50 times] can show them as a separate structure detached on all sides from the ball of the planet.
Space Weather News for May 25, 2018 http://spaceweather.com https://www.facebook.com/spaceweatherdotcom JELLYFISH SPRITES OVER OKLAHOMA: Last night in Oklahoma, a swarm of jellyfish sprites flashed above an intense thunderstorm approaching Oklahoma City. A photographer caught the display at nearly point-blank range, only ~80 miles away, which is unusually close for these forms of upward-directed lightning. Visit today's edition of Spaceweather.com to learn more about jellyfish sprites and why more of them may be in the offing. Remember, SpaceWeather.com is on Facebook!
A magnetosphere is that area of space, around a planet, that is controlled by the planet's magnetic field. The shape of the Earth's magnetosphere is the direct result of being blasted by solar wind. The solar wind compresses its sunward side to a distance of only 6 to 10 times the radius of the Earth. A supersonic shock wave is created sunward of Earth called the Bow Shock. Most of the solar wind particles are heated and slowed at the bow shock and detour around the Earth in the Magnetosheath. The solar wind drags out the night-side magnetosphere to possibly 1000 times Earth's radius; its exact length is not known. This extension of the magnetosphere is known as the Magnetotail. The outer boundary of Earth's confined geomagnetic field is called the Magnetopause. The Earth's magnetosphere is a highly dynamic structure that responds dramatically to solar variations. Credit: NASA/Goddard/Aaron Kaase
A camera mounted ahead caught this image of Starman, in Elon Musk’s red Tesla Roadster, as car and mannequin left Earth behind. Calculations by astronomers in the days after the launch suggest the payload reached a speed of 20.8 miles per second (33.5 km/sec) after the last burn, a faster speed than expected. Image via SpaceX. Last Tuesday (February 6, 2018), SpaceX’s Falcon Heavy successfully lifted off from Launch Complex 39A at Kennedy Space Center in Florida. Falcon Heavy is now the world’s most powerful operational rocket by a factor of two, providing a heavy-lift capability not seen since the Apollo era in the late 1960s and early ’70s, when mighty Saturn V rockets lifted astronauts to the moon. Falcon Heavy’s launch last Tuesday was a test flight, its maiden voyage, meant to prove the concept of the rocket itself (which is in essence three of SpaceX’s Falcon 9 rockets joined together). It definitely did! But SpaceX founder and CEO Elon Musk, as always, went further. He and his team placed Musk’s 2008 Tesla Roadster at the top of the rocket, with the goal of blasting it into an elliptical orbit between Earth and Mars. The orbit would, at times, bring the car – with its passenger, a mannequin nicknamed Starman, dressed for space – near Mars. The Falcon Heavy rocket test was a major success and a thrill for space fans. After livestreaming views from StarMan’s vantage point in Earth orbit SpaceX reignited the upper stage’s engine one last time, giving the Tesla a push beyond Earth’s orbit.
Humanity’s farthest and longest-lived spacecraft, Voyager 1 and 2, achieve 40 years of operation and exploration this August and September. Despite their vast distance, they continue to communicate with NASA daily, still probing the final frontier. Their story has not only impacted generations of current and future scientists and engineers, but also Earth’s culture, including film, art and music. Each spacecraft carries a Golden Record of Earth sounds, pictures and messages. Since the spacecraft could last billions of years, these circular time capsules could one day be the only traces of human civilization.
Mars seen by the Viking oriter. Image via NASA/JPL/USGS By Andrew Coates, UCL Europe has been trying to land on Mars since 2003, but none of the attempts have gone exactly according to plan. A couple of months ago, the ExoMars Schiaparelli landing demonstrator crashed onto the planet’s surface, losing contact with its mothership. However, the mission was partially successful, providing information that will enable Europe and Russia to land its ExoMars rover on the Red Planet in 2021. Now European research ministers have finally agreed to give the mission the outstanding €400m it needs to go ahead. A lot is at stake as the rover is poised to uniquely drill under the harsh Martian surface to search for signs of past, or even present, life. With the best of human endeavor, we must learn, try again and not give up. As leader of the international Panoramic Camera team on the rover, which will among other things provide surface geological and atmospheric context for the mission, I am one of many scientists working very hard to make it work. PanCam is one of nine state-of-the-art instruments which will help us analyze subsurface samples. The reason it is so hard to land on Mars is that the atmospheric pressure is low, less than 1% of Earth’s surface pressure. This means that any probe will descend very rapidly to the surface, and must be slowed. What’s more, the landing has to be done autonomously as the light travel time from Earth is three to 22 minutes. This delay transmission means we can’t steer the rapid process from Earth. NASA and Russia have had their own problems with landings in the past, before the spectacular successes with the US missions Viking, Pathfinder, Spirit,Opportunity, Phoenix and Curiosity
Our sun is located about two-thirds of the way out from the center of the Milky Way. Illustration via Caltech. The planets in our solar system orbit around the sun. One orbit of the Earth takes one year. Meanwhile, our entire solar system – our sun with its family of planets, moon, asteroid and comets – orbits the center of the Milky Way galaxy. Our sun and solar system move at about about 500,000 miles an hour (800,000 km/hr) in this huge orbit. So in 90 seconds, for example, we all move some 12,500 miles (20,000 km) in orbit around the galaxy’s center. Our Milky Way galaxy is a big place. Even at this blazing speed, it takes the sun approximately 225-250 million years to complete one journey around the galaxy’s center. This amount of time – the time it takes us to orbit the center of the galaxy – is sometimes called a cosmic year.
This artist’s concept puts solar system distances in perspective, but you have to think about it a bit to understand it. The scale bar is in astronomical units (AU), with each set distance beyond 1 AU representing 10 times the previous distance. One AU is the distance from the sun to the Earth, by the way, which is about 93 million miles or 150 million kilometers. Neptune, the most distant planet from the sun, is about 30 AU. Informally, the term solar system is often used to mean the space surrounding our sun, out to the last planet. Astronomers, however, might speak of the solar system as the heliosphere, or sphere of the sun’s influence. Our dominates its own region of space and creates a sort of bubble of charged particles in the space surrounding it. These particles are “blown” out from the sun by the solar wind. It’s this heliosphere that Voyager 1 has now left. NASA says Voyager 1 actually crossed the heliopause, the boundary around the region of the sun’s influence, over a year ago, on August 25, 2012. It’s also possible, though, to picture the solar system as going out to the Oort Cloud, the source of the comets that swing by our sun on long time scales. Beyond the outer edge of the Oort Cloud, the sun’s gravitational influence begins to wane. The inner edge of the main part of the Oort Cloud could be as close as 1,000 AU from our sun. The outer edge is estimated to be around 100,000 AU. So that’s 100,000 times the Earth-sun distance.