Twilight is the time of day between daylight and darkness. Astronomers, the experts on nighttime, recognize three kinds of twilight.
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On summer nights, two famous stars down from high in the northern sky. Eltanin and Rastaban represent the fiery Eyes of the constellation Draco the Dragon.
By mid-July, Jupiter is gone. As darkness falls, Mars and star Spica are closest together for 2014, with Saturn nearby. Venus and Mercury east before dawn.
The year 2014 has a total of five supermoons. They are the two new moons of January, and the full moons of July, August and September. Everything you need to know here.
A farmer captured this photo of a serious storm sweeping through northern Illinois on Monday, June 30.
In twilight in the summer months, at high latitudes, you might see glowing clouds in a dark night sky. They are called noctilucent or “night-shining” clouds.
Look in the northeast on these June evenings – near the star Vega. You’ll see Rastaban and Eltanin, two stars that are bright and close together.
We see only 50% of the moon’s surface at one time. Even so, over time, lunar libration lets careful observers peek at a tiny portion of the moon’s far side.
For a few hours around midnight, in Kansas, temperatures suddenly shot up by 10 degrees F. Meteorologists call it a heat burst. Read how it happens.
A volcano erupting under an immense glacier would have created large lakes of liquid water on Mars in the relatively recent past. And where there’s water, there’s the possibility of life.
North America is predicted to have the best view of a possible new meteor shower from Comet 209P/LINEAR Friday night through Saturday morning (May 23-24, 2014). The Camelopardalids, coming up!
Chance for significant severe weather is possible across the Plains on Mother’s Day. Strong tornadoes and large hail possible.
The constellation Virgo the Maiden fully returns to the early evening sky – with her feet planted on the eastern horizon – by late April and early May.
Happy May Day! A few words about this annual celebration, whose roots are in astronomy.
After a slow start to severe weather season in 2014, Sunday brought storms to the U.S. Central Plains. Monday through Wednesday, the system will move into the U.S. Southeast.
A mythical Celtic god of the sea and the edgewise view into our own Milky Way galaxy, as captured by Glenn Miles Photography in Northern Ireland.
Before and after satellite images of the March 22 landslide near Oso, Washington
As Earth spins under the sky, the stars appear to move. When a camera captures that movement, that’s called a star trail. Plus … an astrophotographer explains how he does it.
No matter what the weather where you are, enjoy these photos from EarthSky friends on Facebook and G+. Signs of spring 2014!
Looking for the constellation Cancer? How to find it here. Plus Cancer’s place in sky history, lore and science.
Just when scientists thought that all butterfly species in the eastern U.S. were identified, researchers stumbled across not one, but two new species, right under their noses.
For astronomers, a binary or double star is a gift from the heavens. Astronomers observe these stars to find telltale clues to each star’s mass.
It’s like a hurricane, but it’s over land. These systems are not uncommon in Australia, and, last weekend, conditions were ripe for one.
Unstable carbon-14 gradually decays to carbon-12 at a steady rate. Scientists measure the ratio of these carbon isotopes to determine how long ago things lived.
2014 unleashed its first X-flare of 2014 on January 7. Space weather experts are calling for a good display of auroras.
Normally these remote galaxies would be too faint to see, even with the Hubble Space Telescope. Astronomers used a bizarre trick of nature to photograph them.
The solstice is behind us. At high northern latitudes, sunlight is returning only briefly each day or casts an eerie twilight glow.
The work could provide insights into the workings of black-hole jets and help us understand the rate of the expansion of the universe.
This new moon at the New Year is also one of the closest moons of the year. The close, new moon will cause tides to be higher than usual.
The amount of U.S. land burned by wildfires during 2013 was 41% lower than the 10-year average, according to preliminary estimates.
Venus is beautiful now! Just don’t wait too many days to look for it. It’ll soon disappear in the glare of sunset.
A new study shows that the risk of injury from tornados and severe storms can be reduced significantly with the use of certain media.
If you photographed the sun at the same time each day – subtracting an hour as needed for Daylight Saving Time – the resulting figure-8 would be an analemma.
A new visualization of events leading to one of the iconic photographs of the 20th century – Earth rising over the moon.
“We might witness a nice, long-tailed comet visible to the naked eye that will leave millions of people with fond memories for a lifetime, or maybe it will be a small comet for sky hunters using binoculars and a good map of its position. Or it might yet break up and vanish.” – Alan MacRobert
Death toll is rising as reports trickle in from storm-damaged areas. Video and images here of Super Typhoon Haiyan.
Scientists have pinpointed the brain region responsible for “illusory contours”—when you perceive imaginary shapes and surfaces against a fragmented background.
September 2013 has been busy for sightings of bright fireballs. The one at 11:33 p.m. local time on September 27 was the 14th fireball sighting in the U.S. in September.
The world’s thinnest glass is just a molecule thick, a serendipitous discovery by scientists, recorded for posterity in the Guinness Book of World Records.
The constellation Capricornus the Sea-goat. How to see it, and a word about its mythology.
American astronomer Asaph Hall discovered Phobos, one of the two Martian moons, on this date in 1877. Did he imagine how well we’d see Mars’ moons today?
So far, scientists have seen a fractured, ice-covered world with tantalizing signs of a liquid water ocean – a possible home for microbial life – under its surface.
A surge of fire activity in northern Siberia, caused in part by high temperatures.
Astronomers are observing the “noodle effect” as the black hole’s powerful gravity stretches and elongates the cloud.
You may be shocked to learn that drinking large quantities of your favorite carbonated soda could be as damaging to your teeth as methamphetamine and crack cocaine use.
Scientists from Nanyang Technological University (NTU) and Lund University, Sweden, have bioengineered a novel molecule which has been proven to successfully kill tumor cells.
Temperatures have been well below average for the Southeast United States for the first half of May 2013. Here’s why.
University of Georgia researchers used a Facebook page to determine the trajectories of tornado debris.
New research aimed at developing ultrasonic microphones with insect-like sensitivity will continue in the rainforests of Colombia and Ecuador.
On February 20, 2013, Death Valley National Park earned designation as an International Dark Sky Park for its pristine views of the starry nighttime sky.
At 62, the Laysan albatross Wisdom is one of the oldest wild birds known to be living in the world today. Yes, her new chick is adorable.
Amazing pictures and video from Hattiesburg, Mississippi as a large tornado strikes the city on February 10, 2013.
Researchers studying corn seeds have found evidence that full “siblings” preferentially feed each other. They describe this behavior as altruism among corn.
Hearty microorganisms float in the harsh air of hailstorms and hurricanes.
Astronomers have used a new method to determine the mass of the planetary nursery around the star TW Hydrae.At a distance of merely 176 light-years from Earth, this is the closest star that is currently forming new planets.
A new study used computer modelling to shed light on the origin of sight in animals, including humans.
Orbiting satellite acquired view of an aurora, seen from above, on October 8, 2012. These northern lights resulted from a storm on the sun several days earlier.
“Where’s the hottest place on Earth” is a contentious issue. Some contenders: Iran’s Lut Desert, China’s Turpan Basin and the badlands in Queensland, Australia.
As of now, it appears that Isaac caused the deaths of nearly 40 people and will result in at least $3 billion in damages.
July 2012 was the fourth straight month in which the Northern Hemisphere set a new monthly land temperature record. It was the fourth-warmest July globally.
Giant sunspot group 1520 – which spans about 10 Earth diameters on the sun’s surface – emitted an X-flare on July 12 at 1653 UTC.
In 2007, we saw the smallest Arctic summertime ice extent since record keeping began. As summer 2012 begins, ice is melting faster now than at this same time in 2007.
Joplin tornado of May 22, 2011 was deadliest single U.S. tornado since 1950 and costliest tornado in world history. See videos. Learn how Joplin is rebuilding.
Good news for penguin lovers! New satellite images show that there are twice as many emperor penguins in Antarctica than previously thought.
At least 11 confirmed tornadoes struck the Dallas-Fort Worth area on April 3, causing damage but no deaths. Here’s what’s known now, plus the best videos.
A 6.7 magnitude earthquake rocked the Philippines on February 6, 2012 killing at least 15 people, with many still missing.
If extra-terrestials visited the moon, they may have left tell-tale signs. It’s worth a look, says a leading scientist, and won’t cost much.
Favorite pics of sunrises and sunsets – with an explanation of why they’re so beautiful! Post your sunrise and sunset images on EarthSky’s Facebook page.
While in space, 12 generations of worms were found to reproduce and develop from egg to adulthood no differently than they would on Earth.
Our brain cells munch on themselves, to keep the body from starving. A new study sheds light on the role this plays in regulating appetite.
Featured this week, lifelike robots – plus lakes on Jupiter’s moon and an eclipse of the midnight sun. Song of the week from Ocote Soul Sound.
Earth might have been spared from a collision with Mars or Venus by the process in which a fifth giant world was ejected from our solar system.
A haboob – an enormous dust storm – swept through parts of Lubbock, Texas on the evening of Monday, October 17, 2011.
Coastal fish farms seem to do less harm to nearby plants and animals than previously believed, a new study reveals.
The largest of the Texas fires – the Bastrop fire near Austin in Central Texas – is said to be 30 percent contained today.
UPDATE: Sunday, August 28, 5:40 p.m. EDT (21:40 UTC). Tropical Storm Irene has been gradually weakening and is beginning to lose tropical characteristics.
The huge stock of carbon contained in tundra could increase atmospheric CO2 drastically, when released by a fire.
Watch a video that shows tropical storm Arlene as it forms in the Gulf of Mexico on June 27, 2011.
A ten-year study shows that loggerhead turtles go back to the same spots year after year.
Astronomers captured light from 40,000 galaxies and discovered that even in the early universe, galaxies were either awake or asleep.
Growing scarcity of girls and women has tilted the balance of the sexes and the rich and poor in nations where “gendercide” is practiced on a large scale.
The mind is a great statistician, say psychologists studying two types of perception.
This Facebook map of the world shows the connections between about 10 million friends.
November meteor showers, a frozen zoo, butterfly medicine, a Bill of Rights for aliens – plus some great music – all this week on EarthSky 22.