June Solstice: Longest and Shortest Day of the Year
The June solstice is the summer solstice in the Northern Hemisphere and the winter solsticein the Southern Hemisphere.
The June Solstice. (Not to scale)
The date varies between June 20 and June 22, depending on the year, and the local time zone.
June Solstice in Baku, Azerbaijan was on
Thursday, 21 June 2018, 14:07 AZT (Change city)
June Solstice in Universal Coordinated Time was on
Thursday, 21 June 2018, 10:07 UTC
- Local times for June Solstice 2018 worldwide
- Day and Night map for June Solstice 2018
- Equinoxes and solstices from 2000–2049
Zenith Furthest Away from the Equator
A solstice happens when the sun’s zenith is at its furthest point from the equator. On the June solstice, it reaches its northernmost point and the Earth’s North Pole tilts directly towards the sun, at about 23.4 degrees.
It’s also known as the northern solstice because it occurs when the sun is directly over the Tropic of Cancer in the Northern Hemisphere.
11 Facts About the June Solstice
Meaning of Solstice
“Solstice” (Latin: “solstitium”) means sun-stopping. The point on the horizon where the sun appears to rise and set, stops and reverses direction after this day. On the solstice, the sun does not rise precisely in the east, but rises to the north of east and sets to the north of west, meaning it’s visible in the sky for a longer period of time.
Although the June solstice marks the first day of astronomical summer, it’s more common to use meteorological definitions of seasons, making the solstice midsummer or midwinter.
Astronomical terms & definitions
Solstices in Culture
Over the centuries, the June solstice has inspired countless festivals, midsummer celebrations and religious holidays.
One of the world’s oldest evidence of the summer solstice’s importance in culture is Stonehenge in England, a megalithic structure which clearly marks the moment of the June solstice.
In the Southern Hemisphere, where the June solstice is known as the shortest day of the year, it marks the first day of astronomical winter, but the middle of winter in meteorological terms.
Midnight Sun or Polar Night?
On the June solstice, the midnight sun is visible (weather permitting) throughout the night, in all areas from just south of the Arctic Circle to the North Pole.
On the other side of the planet, south of the Antarctic Circle there’s Polar Night, meaning no Sunlight at all, on the June solstice.
Solstice Dates Vary
Even though most people consider June 21 as the date of the June solstice, it can happen anytime between June 20 and June 22, depending on which time zone you’re in. June 22 solstices are rare – the last June 22 solstice in UTC time took place in 1975 and there won’t be another one until 2203.
The varying dates of the solstice are mainly due to the calendar system – most western countries use the Gregorian calendar which has 365 days in a normal year and 366 days in a Leap Year.
A tropical year is the time it takes the Earth to orbit once around the Sun. It is around 365.242199 days long, but varies slightly from year to year because of the influence of other planets. The exact orbital and daily rotational motion of the Earth, such as the “wobble” in the Earth’s axis (precession of the equinoxes), also contributes to the changing solstice dates.
Moving to Other Seasons
After the June solstice, the sun follows a lower and lower path through the sky each day in the Northern Hemisphere until it reaches the point where the length of daylight is about 12 hours and eight to nine minutes in areas that are about 30 degrees north or south of the equator.
Areas 60 degrees north or south of the equator have daylight for about 12 hours and 16 minutes. This is the September Equinox, the Autumnal Equinox in the Northern Hemisphere.
Earth does not move at a constant speed in its elliptical orbit. Therefore the seasons are not of equal length: the times taken for the sun to move from the March Equinoxto the June solstice, to the September equinox, to the December solstice, and back to the March equinox are roughly 92.8, 93.6, 89.8 and 89.0 days respectively.
The consolation in the Northern Hemisphere is that spring and summer last longer than autumn and winter.
Source: Time and Date
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Long Way From Home [EN]
This picture of a crescent-shaped Earth and Moon – the first of its kind ever taken by a spacecraft – was recorded Sept. 18, 1977, by NASA’s Voyager 1 when it was 7.25 million miles (11.66 million kilometers) from Earth. The moon is at the top of the picture and beyond the Earth as viewed by Voyager
Source: NASA
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Yer kürəsinə təhlükəli asteroid yaxınlaşır [AZ]
Şənbə günü, iyunun 24-də, Yer kürəsinə potensial təhlükəli nəhəng asteroid yaxınlaşacaq.
Oxu.Az-ın xəbərinə görə, bu barədə Fobos nəşri məlumat yayıb.
Səma cisminin diametri 230 metr təşkil edir. Asteroid saatda 45 min kilomter sürətlə hərəkət edir və Yerdən üç milyon km məsafədə keçəcək.
Alimlər hesablayıblar ki, Yer kürəsi asteroidlə toqquşacağı təqdirdə Xirosima atılan atom bombasından sonra baş verən partlayışdan 300 dəfə güclü partlayış qeydə alınacaq.
Mənbə: oxu.az
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Unikal teleskop hazırlanacaq – ABŞ və Rusiya alimləri razılaşdı [AZ]
NASA unikal teleskopun hazırlanması üzrə rus alimləri ilə razılığa gəlib.
Bildirilir ki, Amerika Kosmik Agentliyi sınaqdan keçirmək məqsədilə maliyyələşdiriləcək 22 innovasiya proyektinin siyahısını təqdim edib. Əvvəllər ayrı-ayrı qruplara təklif edilmiş elmi proyektlərdən 15-i artıq ilk mərhələsindən keçib. Onların 9 aylıq fəaliyyəti üçün 125 min dollar ayrılıb.
İlk mərhələ üçün nəzərdə tutulmuş ideyalara NASA əməkdaşı rusiyalı alim Vçislav Turışevin layihəsi daxildir. “Kosmik teleskop” adlanan layihədə Günəş Yer Planetinin öyrənilməsi üçün cəzibə linzası kimi istifadə edilir. Layihə çərçivəsində naviqasiya aparatı ilə bağlı problemlər, cihazlarla idarəetmə məsələlərinin tam şəkildə həll olunması gözlənilir.
Unikal teleskop 600 astronomik nöqtəyə çıxış əldə edəcək.
Mənbə: metbuat.az
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Fevralın 26-da bu ilin ilk Günəş tutulması baş verəcək [AZ]
“İslaminSesi”nin məlumatına görə, Azərbaycan Milli Elmlər Akademiyasının (AMEA) Şamaxı Astrofizika Rəsədxanasının direktor müavini Xıdır Mikayılov APA-ya bildirib ki, proses saat 16:12-də başlayacaq, saat 18:54-də maksimumda olacaq, saat 21:35-də bitəcək. O qeyd edib ki, həlqəvari Günəş tutulması Amerika, Cənubi Afrikanın qərbində müşahidə olunacaq. X. Mikayılov vurğulayıb ki, bu hadisəni Azərbaycandan izləmək mümkün olmayacaq.
Qeyd edək ki, bu il 2 Ay və 2 Günəş tutulması hadisəsi baş verəcək. İlk ay tutulması fevralın 11-də qeydə alınıb. Növbəti Ay tutulması avqustun 7-də, ikinci Günəş tutulması isə avqustun 21-də olacaq. Bu hadisələrin insanlar üçün heç bir təhlükəsi yoxdur və adi astronomik hadisədir.
Mənbə: İslaminSesi.az
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NASA Telescope Reveals Largest Batch of Earth-Size, Habitable-Zone Planets Around Single Star [US]
NASA’s Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.
The discovery sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system. All of these seven planets could have liquid water – key to life as we know it – under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.
“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”
At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets.
This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system. Assisted by several ground-based telescopes, including the European Southern Observatory’s Very Large Telescope, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.
The new results were published Wednesday in the journal Nature, and announced at a news briefing at NASA Headquarters in Washington.
Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them, allowing their density to be estimated.
Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces. The mass of the seventh and farthest exoplanet has not yet been estimated – scientists believe it could be an icy, “snowball-like” world, but further observations are needed.
“The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star,” said Michael Gillon, lead author of the paper and the principal investigator of the TRAPPIST exoplanet survey at the University of Liege, Belgium. “It is also the best target yet for studying the atmospheres of potentially habitable, Earth-size worlds.”
In contrast to our sun, the TRAPPIST-1 star – classified as an ultra-cool dwarf – is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun. The planets also are very close to each other. If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.
The planets may also be tidally locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong winds blowing from the day side to the night side, and extreme temperature changes.
Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. In the fall of 2016, Spitzer observed TRAPPIST-1 nearly continuously for 500 hours. Spitzer is uniquely positioned in its orbit to observe enough crossing – transits – of the planets in front of the host star to reveal the complex architecture of the system. Engineers optimized Spitzer’s ability to observe transiting planets during Spitzer’s “warm mission,” which began after the spacecraft’s coolant ran out as planned after the first five years of operations.
“This is the most exciting result I have seen in the 14 years of Spitzer operations,” said Sean Carey, manager of NASA’s Spitzer Science Center at Caltech/IPAC in Pasadena, California. “Spitzer will follow up in the fall to further refine our understanding of these planets so that the James Webb Space Telescope can follow up. More observations of the system are sure to reveal more secrets.”
Following up on the Spitzer discovery, NASA’s Hubble Space Telescope has initiated the screening of four of the planets, including the three inside the habitable zone. These observations aim at assessing the presence of puffy, hydrogen-dominated atmospheres, typical for gaseous worlds like Neptune, around these planets.
In May 2016, the Hubble team observed the two innermost planets, and found no evidence for such puffy atmospheres. This strengthened the case that the planets closest to the star are rocky in nature.
“The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets,” said Nikole Lewis, co-leader of the Hubble study and astronomer at the Space Telescope Science Institute in Baltimore, Maryland. NASA’s planet-hunting Kepler space telescope also is studying the TRAPPIST-1 system, making measurements of the star’s minuscule changes in brightness due to transiting planets. Operating as the K2 mission, the spacecraft’s observations will allow astronomers to refine the properties of the known planets, as well as search for additional planets in the system. The K2 observations conclude in early March and will be made available on the public archive.
Spitzer, Hubble, and Kepler will help astronomers plan for follow-up studies using NASA’s upcoming James Webb Space Telescope, launching in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone, and other components of a planet’s atmosphere. Webb also will analyze planets’ temperatures and surface pressures – key factors in assessing their habitability.
NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate. Science operations are conducted at the Spitzer Science Center, at Caltech, in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at Caltech/IPAC. Caltech manages JPL for NASA.
For more information about Spitzer, visit:
For more information on the TRAPPIST-1 system, visit:
https://exoplanets.nasa.gov/trappist1
For more information on exoplanets, visit:
https://www.nasa.gov/exoplanets
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