Ten years ago, Venus crossed the sun's face. Most of us will never get to see it again in our lifetimes.

A look at the most recent transit of Venus, which occurred more than a century ago and was visible in the clear sky above Hawaii.

The past two years' events have taught many of us a valuable lesson: we should never take anything for granted. The anarchy caused by the pandemic wreaked havoc on relationships, commerce, and the liberties we typically take for granted without giving them a second thought.

Traveling the world in search of some of the most impressive sights in the heavens has been my primary focus during my professional life. Because of how convenient the worldwide travel network is, I've been able to cross off almost every item on my astronomical bucket list. This is all down to the convenience of the global travel network. I didn't wholly appreciate how fortunate I've been until 2020, when everything reached a complete standstill.

Now that the opportunities have come back, some occasions just don't come around very often. That's why, ten years ago, when the idea of a global lockdown didn't even cross my mind, I set out on a journey with a round-trip distance of 16,000 miles (26,000 kilometers) to observe the transit of Venus. This event would never happen again in my lifetime.

This event was made possible due to the ability to travel and the remarkable predictive potential of modern astronomy. It is nearly impossible for anyone to be caught off guard by a celestial event; except for meteor storms, unexpected comets, and supernovas, it is almost impossible for anyone to be caught off guard by a cosmic event. For example, from now on, eclipses won't be able to sneak up on any of us again.

Of course, we have not always been able to make such accurate forecasts in the past. Galileo (opens in new tab) made a groundbreaking discovery in 1610 when he witnessed the phases of Venus for the first time. He later published his sketches of the phenomenon in 1623. Later on, his contemporary Johannes Kepler (opens in new tab) would produce the tables of the solar system that are considered the most accurate in the world. These tables were based on the best observations available to Kepler at the time. The arrival of these tables was eagerly awaited, and while they were excellent for the occasion, they were not flawless.

Within those priceless tables, Kepler made the bold prediction that the planets Mercury and Venus would both make their way across the face of the sun in the year 1631. In addition, he forecasted a close encounter between Venus and the sun in the year 1639 and another transit in the year 1761. The Venus transit of 1631 took place precisely on time in December, but unfortunately, those who wanted to observe it were thwarted by adverse weather and only minimal visibility across Europe. It was the only phase of Venus that Galileo did not attend during his lifetime; however, he did live long enough to see the subsequent stage of Venus, unbeknownst to him. Galileo must have been disappointed not to see one in his lifetime.

Jeremiah Horrocks, an English astronomer, made use of his observations and his talent for mathematics to improve Kepler's tables in 1639. It was only a few weeks before the actual event, but he correctly predicted that there would be a transit of Venus in December of that year. Horrocks was one of the few people in the world who witnessed Venus's transit because Kepler had made an error in his calculations. Even though he was getting on in years, Galileo was still alive, but in a terrible twist, by the year 1638, he had lost virtually all of his sight.

Since then, only six transits of Venus have taken place: in 1761 (as Kepler had predicted), in 1769, in 1874, in 1882, in 2004, and 2012. They occur in two sets, with an eight-year gap between each pair and more than a century gap between each group. Because the next transit won't take place until 2117, I made it a point to be present for the entirety of the previous one, which took place ten years ago.

The transit that occurred in 2012 lasted for almost six and a half hours, commencing on June 5 and continuing into the following day, with visibility being at its best over the Pacific Ocean. It was visible in many parts of the world, including the United States, Europe, East Africa, Asia, and Australia. However, one site, in particular, offered unobstructed visibility at a high altitude in a piece of paradise: Hawaii.

I planned to see Venus's transit from the slopes of Mauna Kea, the tallest volcano on Earth, together with hundreds of other people interested in astronomy. Its summit is home to some of the world's most powerful and prolific telescopes, but staying there for an extended period in such thin air can be hazardous if you have not initially adjusted to the conditions.

I was rapidly out of breath when I made the brief ascent to the peak. The Visitor Information Station, situated at an elevation of 9,200 feet (2.8 kilometers) above sea level, is much less difficult to access and provides visitors with an excellent foundation from which to set up their telescopes.

As a result of many of those tracking the transit having observed the breathtaking partial lunar eclipse on June 3 and 4, immediately upon or shortly after arriving in Hawaii, spirits were high. The eclipse was a spectacular experience in and of itself, but it was little more than a teaser for what was to come after it.

At the Visitor Information Station on the morning of June 5, I assembled two miniature telescopes located among dozens of other telescopes of varying sizes and styles. Mine were the only two I could somewhat take on such a lengthy journey, and I had spent many days in London putting them through their paces with my photographic gear to guarantee that I would be able to make accurate observations.

(You must safeguard both your eyes and your equipment by using a solar filter to witness transits of Venus or Mercury as well as solar eclipses safely.)

I had the telescopes set up on Mauna Kea in a concise amount of time, and I was ready to go well before the significant event. As the morning progressed, there was an increasing expectancy, and the audience became increasingly quiet. Then, just a few minutes after local noon, the dark edge of Venus's silhouette emerged on the sun's surface, leaving a dent in its limb.

The pitch-black night side of Venus was observed in great relief against the solar disk using adequately filtered telescopes. It appeared significantly larger or darker than any other fascinating sunspot group on that day. This view of the sun's photosphere in "white light" also reveals granulation on its surface.

As Venus' night-side began its quick entry onto the sun's disk, the gathering of people watching the sky erupted in a chorus of vocal wonder, culminating in cheers of delight; the entire process took just over 15 minutes.

The clean air made every vista appear as crisp as a razor. The following hours provided sufficient opportunities to admire our neighboring planet's sheer grandeur and contrast, which is only 26.8 million miles away (43.1 million km). When viewed via a telescope, Venus appeared to be exceedingly magnificent as it subtended nearly an entire arcminute.

Standing atop a massive terrestrial volcano and looking out at the planet with the most volcanoes in the solar system, I couldn't help but feel that I was much closer to Venus than I actually was.

I also became aware of how much of what was happening during the event I could understand because of the hard work of astronomers from generations past. For example, I wasn't the first to travel from London to Hawaii to witness a Venus transit.

In 1874, George Tupman led an expedition from England to Oahu. Subsequently, he published a comprehensive compilation of observations gleaned from various locales. Like James Cook before him in 1761, Tupman was well aware of the critical nature of making the most of opportunities like this.

Nearly 150 years ago, the well-known astronomer Edmund Halley (opens in a new tab) postulated that if astronomers carefully timed transits from numerous sites, they would be able to determine the size of the solar system. Observing transit from two different locations allows for the creation of a baseline: the contact points, which are the points at which the edge of a planet and the edge of the sun appear to touch, seem to occur at slightly different times due to the parallax angle. By measuring the difference in timing between the contact points, astronomers can use simple trigonometry to determine the distances between the transiting planet and the sun.

The sheer rarity of Venus transits, coupled with the planet's relative closeness and apparent size, instilled a sense of urgency within the astronomical community. Mercury transits were also used to make these critical decisions, but the sheer rarity of Venus transits heightened the sense of urgency.

Venus' apparent width was approximately 3 percent of the sun's, making it relatively easy for frequent eclipse observers to spot it. This image was captured with a specialized Hydrogen-Alpha (H) telescope, which reveals the intricate chromosphere of the sun. It depicts the entire solar disk.

Even though astronomers are more confident in their estimates of the distances between celestial objects, the same sense of urgency to witness something rare and extraordinary was the driving force behind the large number of people who gathered to make the most of the Venus transit ten years ago.

After all, only a tiny percentage of those alive during the 2012 eclipse will survive long enough to watch the next one, which will take place in 2117. I don't think I'll be one of those lucky few, but if I make it to 131 years old, you can bet I'll have much to say about it when I get back!

To our good fortune, Mercury transits occur approximately thirteen times a century.

Mercury transits, like Venus transits, don't occur at regular intervals; we've already had two (in 2016 and 2019), but the next one won't come for another 10.5 years at the earliest.

Transits are uncommon because Mercury's and Venus' orbits are tilted relative to the Earth's. Mercury's orbit is tilted by 7 degrees, and Venus's orbit is rocked by 3.4 degrees. The planet must reach what is known as inferior conjunction, which is when the Earth is closer to the sun than it is to itself, while at the same time, it must strike one of the two nodes where its orbit crosses over that of the Earth.

This is an unusual combination to find. Because of its proximity to the sun and the resulting acceleration of its orbital period, Mercury is in a state of inferior conjunction with greater frequency than any other planet. This results in a more significant number of opportunities for transit to occur. The moon, though, is another natural object in our sky that may cause transits, and it can do so at an even higher frequency than the sun.

The moon creates between two and five transits each year, and it does so by coming into conjunction with the sun every 29.5 days. This conjunction makes the moon appear enormous in our sky. Although we refer to these occurrences as solar eclipses, they are correctly classified as transits because we observe one object pass in front of another.

Our cosmic buddy will keep us busy throughout the long wait until 2032 by providing us with several opportunities to view solar eclipses. The next partial solar eclipse will take place on October 25, and it will be visible in areas of Asia and Africa, Europe, and the Middle East. A total solar eclipse will take place over the South Pacific on April 20, 2023. This will be visible from a portion of Western Australia, western Indonesia, and Papua New Guinea. In the latter half of next year, on October 14, 2019, an annular solar eclipse, sometimes known as a "ring of fire" eclipse, will take place over South America, Central America, and the United States.

Between now and the end of 2023, a vast majority of people living on Earth will have had the opportunity to witness a portion of the sun's face being obscured by the face of the new moon. In April 2024, the United States will see a solar eclipse that will be visible throughout a large portion of the country, bringing back memories of the breathtaking Great American Solar Eclipse that occurred in 2017.

The vast majority of eclipse chasers will have to travel and organize their trips, just like scientists have done for years, to get the best possible views of the eclipse. Now is the time to start preparing for skywatching in October and beyond. However, if you expect to see the next transit of Venus, the best course of action is to maintain a healthy diet, exercise regularly, and do anything else that might extend your life. Best of luck!

 

 

Article source : https://www.livescience.com/venus-crossed-sun-10-years

Image source   : https://pixabay.com/id/vectors/ruang-angkasa-matahari-air-raksa-7305292/

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