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Slowing down an asteroid by just one-tenth of a second makes all the difference.
This graph shows the number of sunspots seen each year for 400 years (from 1600 to 2000). There were almost no sunspots during the Maunder Minimum. During the Dalton Minimum, there were fewer sunspots than normal. //
The first written record of sunspots was made by Chinese astronomers around 800 B.C. Court astrologers in ancient China and Korea, who believed sunspots foretold important events, kept records off and on of sunspots for hundred of years. An English monk named John of Worcester made the first drawing of sunspots in December 1128. //
It would appear that sunspots not only have a connection to geomagnetic activity at Earth, but they play a role in climate change as well. In the last thousands of years, there have been many periods where there were not many sunspots found on the Sun. The most famous is a period from about 1645 to 1715, called the Maunder Minimum. This period corresponds to the middle of a series of exceptionally cold winters throughout Europe known as the Little Ice Age. Scientists still debate whether decreased solar activity helped cause the Little Ice Age, or if the cold snap happen to occur around the same time as the Maunder Minimum. In contrast, a period called the Medieval Maximum, which lasted from 1100 to 1250, apparently had higher levels of sunspots and associated solar activity. This time coincides (at least partially) with a period of warmer climates on Earth called the Medieval Warm Period. Sunspot counts have been higher than usual since around 1900, which has led some scientists to call the time we are in now the Modern Maximum.
Good morning. It's May 1, and today's photo is ridiculously awesome. Taken by the James Webb Space Telescope, it features the sharpest infrared image of the Horsehead Nebula captured to date—it is so zoomed in we can only see the mane. Even so, the image covers an area that is nearly one light-year across, or about 7.6 trillion km.
The Horsehead Nebula is fairly close to Earth, as these things go, about 1,300 light-years. So, it is within our galaxy. In addition to the prominent star at the top of the image and a handful of other stars with six diffraction spikes, the rest of the objects in this image are distant galaxies.
In astronomy, a planetary transit is when a planet closer to the Sun passes in front of the Sun's disc as seen from a more distant planet. From the Earth, transits of Mercury and Venus are visible; recently, observers were treated to these spectacles in back-to-back years: 2003 and 2004.
In the run-up to the 2004 transit of Venus, I became obsessed with one of those silly questions which, once they sink their claws into one's mind, won't go away without being answered yes or no. Is there ever a simultaneous transit of Mercury and Venus visible from the Earth?
The naïve answer is, “Of course not (you idiot)! Transits can occur only when inferior conjunction with the inner planet coincides with its crossing the ecliptic. Transits of Venus always occur in June and December, transits of Mercury in May and November, and thus a simultaneous transit can never happen.”
But this doesn't take into account the evolution of planetary orbits over time. Analytical planetary theories such as VSOP87 are useless beyond the period for which they are fit (say, −4000 to +8000 years Gregorian). To go beyond that, you need to do full-up numerical integration of the motion of the Sun and planets.
Well, that's what computers are for, isn't it? So, I found a high-precision numerical integration code for the Solar System written by Steve Moshier, built a back-end to search for transits, and set it looking for this extraordinarily rare event. Since I didn't want to burn months of computing time with nothing to show for it, I decided to prepare a canon of all Solar System transits (excluding marginal graze events) visible in the time interval I chose, namely a quarter million years centred on the start of the so-called “Common Era”. Here it is.
There are about 200 billion stars in our Milky Way galaxy. Over the next million years our descendents will spread among the stars in an exponential explosion of life, remaking the galaxy as surely as life has remolded Earth in its own image. //
Imagine the variety of worlds and wealth of living species flourishing upon them! Water worlds, desert planets, mountains that reach above the sky—every habitat imagined in science fiction will become real, and many more yet to spring from the imagination of world-makers born half a million years from now.
Terranova is a highly premature anticipation of this exhilarating milestone in the endless adventure of life and intelligence. Every day around 11 a.m. Universal Time a new planet is created using random parameters, and an image of it, as seen from the bridge from your approaching starship, is produced.
“If they existed, they would be here”, said Fermi. So where are they? Nowhere in evidence. Intelligent beings with technologies advanced millions of years beyond our own, spread to the far ends of the galaxy, should not be difficult to detect. We already possess the means to detect even primitive technological civilisations like our own at a distance of hundreds of light years.
If they existed, they—the first intelligent species to expand outward among the stars—would be here. And since we look around and see nobody but ourselves, then it is only reasonable to conclude, “We are here, so we are them.”
Image was captured during Martian spring, on May 21, by Mars Reconnaissance Orbiter's HiRISE camera
In Mars' northern hemisphere, the snow and ice seen on the dunes is made of carbon dioxide - or, dry ice
As it reacts to sun, the gas that escapes carries up the dark sand from below, creating 'beautiful patterns'
Here are two options for future humans to keep us in the habitable zone.
The 2024 total eclipse is in the books. Here's how it looked across the US.
And God said, Let there be light: and there was light. And God saw the light, that it was good: and God divided the light from the darkness. And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day."
The steady rhythm of the night-day, dark-light progression is a phenomenon acknowledged in ancient sacred texts as a given. When it's interrupted, people take notice. In the days leading up to the eclipse, excitement within the Ars Orbiting HQ grew, and plans to experience the last total eclipse in the continental United States until 2045 were made. Here's what we saw across the country.
The Flight Data Subsystem was an innovation in computing when it was developed five decades ago. It was the first computer on a spacecraft to use volatile memory. Most of NASA's missions operate with redundancy, so each Voyager spacecraft launched with two FDS computers. But the backup FDS on Voyager 1 failed in 1982.
Due to the Voyagers' age, engineers had to reference paper documents, memos, and blueprints to help understand the spacecraft's design details. After months of brainstorming and planning, teams at JPL uplinked a command in early March to prompt the spacecraft to send back a readout of the FDS memory.
The command worked, and Voyager.1 responded with a signal different from the code the spacecraft had been transmitting since November. After several weeks of meticulous examination of the new code, engineers pinpointed the locations of the bad memory.
"The team suspects that a single chip responsible for storing part of the affected portion of the FDS memory isn’t working," NASA said in an update posted Thursday. "Engineers can’t determine with certainty what caused the issue. Two possibilities are that the chip could have been hit by an energetic particle from space or that it simply may have worn out after 46 years." //
"Although it may take weeks or months, engineers are optimistic they can find a way for the FDS to operate normally without the unusable memory hardware, which would enable Voyager 1 to begin returning science and engineering data again," NASA said.
This website is available as a resource for eclipse and transit records and information, but will not be updated. For the latest on future eclipses from NASA, please visit https://science.nasa.gov/eclipses/
Terry Richardson, Senior Instructor of Astronomy & Physics at the College of Charleston designed a "Make Your Own Safe Solar Viewer" for the upcoming solar eclipse, sunspot cycle 25 and beyond. This set includes our L14810 achromat (52mm diameter by 600mm focal length) and a Barlow lens with a focal length of -27mm. For the achromat: Place the crown (double convex) with its strongest curve against the negative side of the flint. Use a couple pieces of masking tape on the edges to hold them together. The crown side faces the sky. Using an achromat instead of a single element lens you will get to see more of the sunspots and less blue fringe around the sun (chromatic aberration).
From Eratosthenes' circumference to black holes, we've learned a lot about the cosmos.
2024 Total Eclipse: Where & When
Eclipse Explorer
Award-winning solar astrophotographer Eduardo Schaberger shares his stunning photos of the Sun - and talks about his fascination with our closest star.
Photographing the Sun using a hydrogen-sensitive telescope reveals textures and details invisible to the naked eye: a swirling, volatile world of moving plasma.
Q: Why do planets, just like our moon, have their sidereal paths almost the same (with only slight deviation) as that of the ecliptic? Is it mere coincidence? Or is there a better solution?
A: The ecliptic is the path through the sky along which the sun seems to travel during the year.
If you flip your perspective around, that means the ecliptic is basically the path of Earth's orbit around the sun, projected onto our view of the sky.
The question "Why do all the planets lie near the ecliptic?" is therefore the same as asking "Why are the orbits of all the planets more or less in the same plane?" Apart from very distant objects like comets, the Kuiper belt, and the Oort cloud, everything in the solar system is orbiting in pretty much the same orientation and going the same direction around the sun. How did that happen?
Keeping a complex topic down to its most basic level, the answer to that is that all the planets formed from the same protoplanetary disc of gas and dust, so there wasn't a bunch of "stuff" out orbiting in random directions that could form planets with wildly different orbital characteristics. The disc was all moving in pretty much the same direction in pretty much the same plane, so when it all conglomerated into planets, they had to keep moving the same way. //
By the 1990s, astrophysicists thought they had planet system formation all figured out. Nice and simple: terrestrial planets form inside the ice line, gas giants form just outside the ice line, and smaller (but still massive compared to the Earth) form a bit further out, and beyond that, there are some oddballs. But then astronomers began discovering exoplanets that break all the rules: planets with highly eccentric and/or highly inclined orbits, massive planets well inside the ice line. Our solar system apparently got lucky and escaped the chaos that appears to be the rule. – David Hammen
Since the US total solar eclipse of 2017, interest in the little device I called the Safe Solar Viewer (SSV) has increased all over the globe. Leading up to the August 2017 total solar eclipse and afterwords, readers who built these safe solar viewers emailed with improvements and suggestions including an SSV with an adjustable image size, a large image SSV, a 3-D printed SSV and an SSV made from a standard cardboard shipping box. That input has been incorporated into the instructions found on this web site and for that reason I now title this site the web pages of the Safe Solar Viewer Community.
These pages provide information anyone can use for safely viewing the partial phases of a solar eclipse by projection using inexpensive optics. Some methods are simple enough for very young children to construct themselves with some parental help and all have a modest cost.