It is a narrow total eclipse zone with an average width of about 70 miles (1 13 kilometers), and the distance from the Pacific coast of Oregon to the Atlantic coast of South Carolina is about 2,500 miles (4,023 kilometers), which will provide a scene that has never been seen in any neighboring area of the United States in the past 40 years.
It is an understatement to say that this is a long-awaited astronomical event. [ISO certified equipment is most suitable for watching the 20 17 solar eclipse]
Looking forward to the "KDSP" for decades, The New York Times published a headline report on August 3rd1,1932, saying that the total solar eclipse that swept New England that day (from the logistics point of view) would be the last "very good" total solar eclipse in the United States 20 17 years ago. Samuel Alfred Mitchell, a professor of astronomy at the University of Virginia, was quoted as saying:
"Therefore, after the solar eclipse of 1932 entered people's memory, we didn't have a chance to watch the total solar eclipse from the mainland of the United States until August 2 1 day of 20 17, that is, 85 years later."
1970 On March 7th, during a live TV broadcast of an eclipse in Valdosta, Georgia, the late Charles Kuralt asked Ken Franklin from Hayden Square in new york about the next "South" that people could see. Franklin went on to mention a solar eclipse still in the distant future: "The next solar eclipse" and "It will cross the whole country and go all the way along Carolina to 20 17." Kurt said, "That will take a long time (47 years)."
"Well," Franklin retorted, "unfortunately, this is the world.
It's hard to say when most people will start the countdown, but you can say that we can start the "official" or "final" countdown this weekend-5:46 am EST on Sunday (July 23rd). This will be the moment of the new moon and the last time before the solar eclipse next month. On Sunday morning, the moon will pass near the sun, but it will be completely invisible. In the nearest place, it will be 2.8 degrees south of the sun, or about 5.5 months below the surface of the sun; This is a complete mistake, so at least there is no solar eclipse this month. Like an astronomical clock, the moon will continue to orbit the earth to keep its long-awaited rendezvous with the sun in late August. 20 17 total solar eclipse: when, where and how to see it (safety)
When the moon and the sun intersect, the interval from one new moon to the next is called "the same" month, which comes from synodus in late Latin, meaning "meeting".
In fact, it's at the new moon. Next month, when the moon returns to the position of the sun, it will approach a point in space (called a "node"). From the earth's point of view, the moon can intersect with the sun to produce an eclipse.
Or astronomer Leslie Lee pelletier mentioned the autobiography Starry Night in his popular article (Harper &; Row, 1965): "Only during the solar eclipse can we notice the moment when the old moon moves eastward, crosses the central line of the sun and becomes a new moon, and this moment has just begun the life of a new month."
Time difference? But wait a minute. The next new moon will appear at 2:30 pm EST on August 2 1 Sunday. This Sunday is the 29.5 th day after the new moon. But it only takes 27.3 days for the moon to orbit the earth once.
Where did the extra 2.2 days come from?
You may be surprised to find that there is more than one lunar month. In addition to the same month, there are stars and moons. If we aim the moon at a specific star in the sky, it will take about 27.3 days for the moon to return to the position where the moon is aimed at a star. In the same time interval, the moon's orbit around the earth will also run a complete orbit.
But if we notice that the arrangement of the moon and the sun is the closest, and then run along the moon for 27.3 days until it reaches that precise point in the sky again, the sun will no longer exist.
In fact, compared with the position of the moon, the position of the sun will move about 30 degrees to the east. Therefore, in order to catch up with the sun in our sky, the moon will have to travel for another two days to reach it. [The following are NASA's suggestions for watching the 20 17 solar eclipse]
The reason why the sun moves eastward is that the earth moves around the sun. Therefore, the position of the sun in the sky is not fixed like a star, but constantly changing; From our earth's point of view, it seems that it will move about 30 degrees eastward relative to the background star every month. Imagine a 360-degree circle divided by 12 (number of months). We will get 30. Of course, the earth's orbit is not a perfect circle. It takes us about 365.2422 days to go around the sun, compared with 360 days, but you can get a general idea. )
That's why it takes only 27 days for the moon to go around the earth, but it only takes more than two days from one new moon to the next.
At the same time, remember that this weekend (Sunday) and the time (5:46 am EST) mark the new moon in July. On August 2 1 day, one month from now, the moon revolves in the sky, and the long-awaited "Great American Eclipse" will finally happen.
Editor's note: Space cooperates with the simulation course to provide this awesome eclipse hunting application to help you enjoy the eclipse experience. Both Apple and Android have free apps, which you can check online.
Joe Rao is a lecturer and guest lecturer at the Hayden Planetarium in new york. He has written articles on astronomy for Natural History magazine, Peasant Yearbook and other publications, and is also a photometeorologist at Fios 1 news in Heihe, new york. Follow us @Spacedotcom, Facebook and Google+. An original article about space. "