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THE PERSEID METEOR SHOWER IS BEGINNING: This week, Earth is entering a stream of debris from Comet 109P/Swift-Tuttle, source of the annual Perseid meteor shower. Specks of dusty debris hitting the top of Earth's atmosphere faster than 110,000 mph are burning up in the night sky, producing a spray of shooting stars from the constellation Perseus. Meteor rates are relatively low now, but they will increase sharply in the nights ahead. Forecasters expect the shower to peak on Aug. 11-13 with perhaps dozens of meteors per hour visible in bright moonlight. Visit Spaceweather.com for observing tips and sky maps.
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.
Traffic, along with weather, will be the chief challenges for people wanting to see the total solar eclipse of August 21, 2017. I analyze how the U.S. population is distributed with respect to the U.S. road network and the path of total solar eclipse to predict how many people will visit the path of totality and the resulting traffic congestion. Using advanced ArcGIS.com software by Esri, U.S. Census data, and a road network model of every street in the USA, I present estimates for where people will gather for the eclipse and in what numbers. The coming total solar eclipse of August 21, 2017 is widely called the Great American Eclipse because it will be so accessible to so many millions of Americans. A total solar eclipse is easily the most spectacular sight in nature when the sky suddenly darkens and the most beautiful object in the sky — the sun’s shimmering corona — becomes visible for two minutes or so. To see a total solar eclipse is an intensely emotional experience and a memory for a lifetime. In the weeks and days before the eclipse, broadcast and social media will alert and excite the public. One key message will be that people wanting to see the total eclipse will need to drive to the 60- to 70-mile-wide path of totality. We have good reasons to expect that there will be large numbers of people who will visit the path of totality on eclipse day: – The path of totality cuts a diagonal path across the nation from Oregon to South Carolina and most Americans live within a day’s drive to the path of totality.
Artist’s concept of a large asteroid passing Earth, via Shutterstock. A pair of space rocks, each with a size of about a third of a mile (half a kilometer), will safely pass by Earth, the first on Monday, May 29, 2017 and the second on June 1. Although both asteroids will pass at very safe distances, they will offer good opportunities for astronomers to study these space rocks by using radar. Good news is one of the asteroids has been visible already through medium-sized telescopes, as the space rock has crossed in front of the stars. In this post, we provide charts for observers suitable for Saturday night, May 27. Asteroid 2017 CS, which has an estimated size of about 1,535 feet (468 meters) will be closest to our planet on Monday, May 29 at 15:44 Universal Time (10:44 a.m.CDT). Although “2017 CS” will pass at about 8 lunar distances (8 times the distance from Earth to moon) the asteroid earlier this week was showing a brightness or magnitude of 13.5, which means it is visible through 8-inch and larger-sized amateur telescopes. The asteroid, which is travelling through space at a speed of 20,430 miles per hour (32,879 km/h), will appear as a slowly moving “star.” Observers should be able to detect the space rock movement in relation to fixed stars after a minute or two of careful observations.
The Hubble Space Telescope team released this composite image in honor of the Hubble Space Telescope’s 27th birthday and wrote: When the Hubble Space Telescope launched aboard the Space Shuttle Discovery on April 24, 1990, astronomers could only dream what they might see. Now, 27 years and more than a million observations later, the telescope delivers yet another magnificent view of the universe — this time, a striking pair of spiral galaxies much like our own Milky Way. These island cities of stars, which are approximately 55 million light-years away, give astronomers an idea of what our own galaxy would look like to an outside observer. The edge-on galaxy is called NGC 4302, and the tilted galaxy is NGC 4298. Although the pinwheel galaxies look quite different because they are angled at different positions on the sky, they are actually very similar in terms of their structure and contents.
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.