Latest news with #astronomy
Arab News
an hour ago
- Science
- Arab News
Solstice ushers in start of summer 2025 on Saturday
RIYADH: The summer solstice, which marks the season's astronomical beginning, will take place on Saturday, June 21, according to the Jeddah Astronomical Society. The Kingdom will witness the solstice at 5.42 a.m. Makkah time, when the sun will be directly overhead above the Tropic of Cancer, latitude . The skies of the Kingdom and the rest of the Northern Hemisphere will witness the summer solstice Saturday at 5:42 am Makkah time. At this moment, the sun will be directly overhead above the Tropic of Cancer, latitude 23.5 degrees north. This year, the summer will last for 93 days. Majed Abu Zahra, head of the Jeddah Astronomical Society, said: 'On this day, the sun rises from the far northeast and sets in the far northwest. At noon, the shadows of objects are the shortest of the year, and the sun's apparent path takes its highest arc northward, placing it at its highest altitude in the sky during the year, especially in areas north of the equator.' The summer solstice occurs when the sun reaches its apparent northernmost point in the sky. This coincides with the Earth reaching a position in its orbit where its axis is tilted at the maximum angle (23.5 degrees) toward the sun, causing the longest day and shortest night of the year in the Northern Hemisphere. In the Southern Hemisphere, the situation is reversed. Abu Zahra added: 'The summer solstice does not occur on the same day every year, but rather between June 20 and 22, due to the difference between the calendar year (365 days) and the tropical year (365.2422 days), along with the gravitational effects of the moon and planets and the slight fluctuations in the Earth's rotation, which are compensated for by adding a leap day every four years.' He said it was important to differentiate between the astronomical summer and climatic summer. Meteorologists consider summer to extend from June 1 to August 31, while in astronomy, summer begins when the sun reaches its maximum altitude — the day of the summer solstice. Abu Zahra said although this was the longest day of the year in terms of the number of hours of sunlight, it was not necessarily the hottest. This is because the oceans, land and atmosphere take time to absorb and store solar energy, and then release it again. This delay in the perception of heat is known as 'seasonal lag,' so temperatures typically peak in July or August. Ancient Greek scholars, led by Eratosthenes, used their observations on the summer solstice to calculate the Earth's circumference with amazing accuracy using simple geometric principles. After the summer solstice, the sun will appear to move southward again in the sky, and daylight hours will gradually decrease until the autumnal equinox on Sept. 22.
The Independent
2 hours ago
- Science
- The Independent
Space signal could reveal how universe turned from dark to light
A radio signal from the early universe, known as the 21-centimetre signal, offers a unique opportunity to understand how the first stars and galaxies emerged. This faint glow originates from over 13 billion years ago, approximately 100 million years after the Big Bang, and is created by hydrogen atoms. Scientists plan to use a radio antenna called REACH (Radio Experiment for the Analysis of Cosmic Hydrogen) to capture these signals and gather data about the universe's beginnings. Researchers developed a model predicting how REACH and the Square Kilometre Array can provide information about the masses and other details of the first stars. The work, published in Nature Astronomy, suggests that radio telescopes like REACH can reveal crucial details about the nature and mass of these early stars, which may have differed from today's stars.
CTV News
2 hours ago
- Science
- CTV News
Sunshine abounds as the summer solstice arrives
A man prepares to enter the water as the sun rises above the Miribel lake, outside Lyon, France, June 18, 2022. (AP Photo/Laurent Cipriani) Peak sunshine has arrived in the Northern Hemisphere — the summer solstice. Friday is the longest day of the year north of the equator, where the solstice marks the start of astronomical summer. It's the opposite in the Southern Hemisphere, where it is the shortest day of the year and winter will start. The word 'solstice' comes from the Latin words 'sol' for sun and 'stitium' which can mean 'pause' or 'stop.' The solstice is the end of the sun's annual march higher in the sky, when it makes its longest, highest arc. The bad news for sun lovers: It then starts retreating and days will get a little shorter every day until late December. People have marked solstices for eons with celebrations and monuments, including Stonehenge, which was designed to align with the sun's paths at the solstices. But what is happening in the heavens? Here's what to know about the Earth's orbit. Solstices are when days and nights are at their most extreme As the Earth travels around the sun, it does so at an angle relative to the sun. For most of the year, the Earth's axis is tilted either toward or away from the sun. That means the sun's warmth and light fall unequally on the northern and southern halves of the planet. The solstices mark the times during the year when this tilt is at its most extreme, and days and nights are at their most unequal. During the Northern Hemisphere's summer solstice, the upper half of the earth is tilted toward the sun, creating the longest day and shortest night of the year. This solstice falls between June 20 and 22. Meanwhile, at the winter solstice, the Northern Hemisphere is leaning away from the sun — leading to the shortest day and longest night of the year. The winter solstice falls between December 20 and 23. The equinox is when there is an equal amount of day and night During the equinox, the Earth's axis and its orbit line up so that both hemispheres get an equal amount of sunlight. The word equinox comes from two Latin words meaning equal and night. That's because on the equinox, day and night last almost the same amount of time — though one may get a few extra minutes, depending on where you are on the planet. The Northern Hemisphere's spring — or vernal — equinox can land between March 19 and 21, depending on the year. Its fall – or autumnal — equinox can land between Sept. 21 and 24. On the equator, the sun will be directly overhead at noon. Equinoxes are the only time when both the north and south poles are lit by sunshine at the same time. What's the difference between meteorological and astronomical seasons? These are just two different ways to carve up the year. While astronomical seasons depend on how the Earth moves around the sun, meteorological seasons are defined by the weather. They break down the year into three-month seasons based on annual temperature cycles. By that calendar, spring starts on March 1, summer on June 1, fall on Sept. 1 and winter on Dec. 1. ___ The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
Forbes
3 hours ago
- Science
- Forbes
Don't Miss This Weekend's Sky Show — The Moon, Venus And A Star Cluster
Early risers on Sunday, June 22, are in for a pre-dawn treat — a triangular arrangement of the waning crescent moon flanked by Venus and the Pleiades star cluster. The three most beautiful naked-eye sights to be had in the night sky will create a stunning panorama just before sunrise. Here's everything you need to know about when and where to see them. To catch this display, head outside about an hour before sunrise and look east. Venus, unmistakably bright at magnitude -4.2, will be shining beneath a 13%-lit waning crescent moon (over 30 times brighter than Venus). To the left of the pair will be the Pleiades (also known as the Seven Sisters and Messier 45), one of the closest open clusters of stars to the solar system. Aside from the brilliance of Venus and the dazzling twinkling stars of the Pleiades, look carefully at the moon's darkened portion — its night side. Despite there being no direct sunlight upon it, it is faintly illuminated. That's Earthshine or planet-shine, sunlight reflected from Earth's oceans and clouds onto the moon. It will create a softly lit lunar disk above Venus — a beautiful sight! The entire spectacle is, of course, a line-of-sight illusion — all three objects extremely far from each other. The moon is about 238,000 miles from Earth, Venus about 150 times farther and the Pleiades around 444 light-years away. Forget all about a telescope. It's what everyone immediately thinks of when they think about astronomy, and it's very often completely irrelevant. You just need naked eyes for this sky event, though a pair of binoculars will enhance the view, especially if you want to appreciate the cluster of stars in the Pleiades and get a close-up of Earthshine on the moon. More important is an observing location with a clear, unobstructed view to the eastern or western horizon, if possible away from city lights — though light pollution makes zero difference to the planets and the moon. If you're up for another early outing, Monday, June 23, will see an even slimmer waning crescent moon closer to the Pleiades — just half a degree away — with Venus remaining nearby. For exact timings, use a sunrise and sunset calculator for where you are, Stellarium Web for a sky chart and Night Sky Tonight: Visible Planets at Your Location for positions and rise/set times for planets. Wishing you clear skies and wide eyes.
Yahoo
4 hours ago
- Science
- Yahoo
Mars cozies up to one of the brightest stars in the sky in 'mind-blowing' conjunction photo
When you buy through links on our articles, Future and its syndication partners may earn a commission. A new photo shows Mars shining like a red star in the night sky, alongside the blue-tinged "Heart of the Lion" star, Regulus. Despite their drastic differences, the two objects currently look remarkably similar. Regulus is the brightest star in the constellation Leo. The point of light is coming from a system containing four stars, arranged into two pairs of two, shining approximately 79 light-years from Earth — or around 2.8 million times farther from our planet than Mars. The system's blue tinge comes from its largest star, a blue subgiant around 4.5 times more massive than the sun. It often appears alongside, or gets eclipsed by, other solar system planets and Earth's moon, because it is situated near the ecliptic — the plane in the night sky where all solar system worlds orbit the sun. Mars and Regulus currently appear very close to one another. This conjunction peaked on June 17, when the pair was less than one degree apart, which is equal to around 1.5 times the diameter of the moon in the night sky. The Red Planet is currently shining very brightly at night because of its position relative to Earth and the sun, making it look like a red star. On June 16, the Virtual Telescope Project captured an incredible image of the two objects with nearly identical brightness, using a 14-inch telescope in Italy. The stellar objects look like perfect mirror images of each other, aside from their striking color contrast. "The beauty of their colors is mind-blowing," Gianluca Masi, an astronomer and founder of the Virtual Telescope Project, told Related: Parisian photographer produces phenomenal, perfectly-proportioned 'planetary parade' portrait If you look hard at the image, you may be able to see a fuzzy, faint spot of light between Mars and Romulus, located slightly closer to the blue star. This is the ghostly trace of the Leo I dwarf galaxy, about 820,000 light-years away: "Capturing it in the same frame as Mars and Regulus is something rare and deeply evocative," Masi said. RELATED STORIES —Mars rises over the moon's horizon at the best possible time —Eerie photo of Mars' horizon took NASA 3 months to capture —See Mars 'peek out' from behind the moon in stunning eclipse photo Mars and Romulus will remain close to one another until June 22, when this conjunction officially ends, according to the BBC's Sky at Night Magazine. The conjunction began on June 11. The two bodies are no longer as close as they were, but they can still be seen together with the naked eye. But you can get a better look at the pair using a decent telescope or a pair of stargazing binoculars. The best time to see it is just after twilight under totally clear skies, according to Live Science's sister site 2025 has already seen several noteworthy conjunctions, including a rare "planetary parade" in February, when all seven solar system worlds were near-perfectly aligned in the night sky. Mars and Mercury will also have close conjunctions with the moon later this month.
