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kottke.org posts about astronomy

A simulated “play-by-play” of a total eclipse

posted by Jason Kottke   Aug 20, 2017

This video from the Weather Channel is pretty neat and useful: a play-by-play of what to expect during the eclipse, from being able to see Venus in broad daylight to animals possibly acting weird to the 360-degree “sunset” that happens about 2 minutes before totality.

Viewing a total solar eclipse from an airplane

posted by Jason Kottke   Aug 18, 2017

On March 8-9, 2016, a total solar eclipse swept across the Pacific Ocean for more than 5 hours. About a year before the eclipse, Hayden Planetarium astronomer Joe Rao realized Alaska Airlines flight 870 from Anchorage to Honolulu would pass right through the path of totality…but 25 minutes too early. Rao called the airline and convinced them to shift the flight time.

Alaska’s fleet director, Captain Brian Holm, reviewed the proposed flight path and possible in-route changes to optimize for the eclipse. The schedule planning team pushed back the departure time by 25 minutes, to 2 p.m.

On the day of the flight, Dispatch will develop the specific flight plan, to find the most efficient route and account for weather and wind. Maintenance and maintenance control will help make sure the plane is ready to go — they even washed all the windows on the right side of the plane.

Captain Hal Andersen also coordinated with Oceanic Air Traffic Control, to make them aware that the flight might require a few more tactical changes then normal.

“The key to success here is meeting some very tight time constraints — specific latitudes and longitudes over the ocean,” Andersen said. “With the flight management computer, it’s a pretty easy challenge, but it’s something we need to pay very close attention to. We don’t want to be too far ahead or too far behind schedule.”

The video was shot by a very excited Mike Kentrianakis of the American Astronomical Society, who has witnessed 20 solar eclipses during his lifetime.

July 11, 2010. That was the eclipse over Easter Island, the one for which hotel room rates were so high that there was no way Kentrianakis could afford it. Instead, he considered attempting a trip to Argentina, where experts predicted there was a 5 percent chance of clear skies. His wife at the time, Olga, urged him not to go — it’s not worth the expense, she insisted. Reluctantly, Kentrianakis stayed home.

“It was the beginning of the end for us,” Kentrianakis says. There were problems in the marriage before that episode, “but it affected me that I felt that she didn’t really appreciate what I loved.” They were divorced the following year.

Kentrianakis doesn’t like to dwell on this, or the other things he’s given up to chase eclipses. He knows his bosses grumbled about the missed days of work. Friends raise their eyebrows at the extremes to which he goes. He’s unwilling to admit how much he’s spent on his obsession.

“There is a trade-off for everything, for what somebody wants,” he says.

A camera on the Deep Space Climate Observatory satellite captured the eclipse’s shadow as it moved across the Earth:

For this year’s eclipse, Alaska Airlines is doing a special charter flight for astronomy nerds and eclipse chasers. Depending on how this eclipse goes, seeing an eclipse from an airplane might be on my bucket list for next time. (via @coudal)

How to predict total solar eclipses

posted by Jason Kottke   Aug 18, 2017

The Exploratorium in San Francisco has produced a great explainer video about the science of predicting total solar eclipses. Each eclipse belongs to a repeating series of eclipses called a Saros cycle that repeats every 18 years 11 days and 8 hours.

Saros 145

There are now 40 active Saros cycles and the August 2017 eclipse belongs to Saros 145, which produced its first total eclipse in June 1909 and will produce its last total eclipse in September 2648.

Infographic of the fascinating timeline of the far future

posted by Jason Kottke   Aug 17, 2017

Timeline of The Far Future

Timeline of the far future is one of my favorite pages on Wikipedia. It details what might happen to humanity, human artifacts, the Earth, the solar system, and the Universe from 10,000 years from now until long past the heat death of the Universe. Information is Beautiful has made a lovely infographic of the timeline.

Reading through the timeline is a glorious way to spend time…here are a few favorites I noticed this time around as well as some from my first post.

August 20, 10,663: “A simultaneous total solar eclipse and transit of Mercury.”

20,000 years: “The Chernobyl Exclusion Zone, the 1,000 sq mi area of Ukraine and Belarus left deserted by the 1986 Chernobyl disaster, becomes safe for human life.”

296,000 years: “Voyager 2 passes within 4.3 light-years of Sirius, the brightest star in the night sky.”

1 million years: “Highest estimated time until the red supergiant star Betelgeuse explodes in a supernova. The explosion is expected to be easily visible in daylight.”

1 million years: “On the Moon, Neil Armstrong’s ‘one small step’ footprint at Tranquility Base will erode by this time, along with those left by all twelve Apollo moonwalkers, due to the accumulated effects of space weathering.”

15.7 million: “Half-life of iodine-129, the most durable long-lived fission product in uranium-derived nuclear waste.”

100 million years: “Future archaeologists should be able to identify an ‘Urban Stratum’ of fossilized great coastal cities, mostly through the remains of underground infrastructure such as building foundations and utility tunnels.”

1 billion years: “Estimated lifespan of the two Voyager Golden Records, before the information stored on them is rendered unrecoverable.”

4 billion years: “Median point by which the Andromeda Galaxy will have collided with the Milky Way, which will thereafter merge to form a galaxy dubbed ‘Milkomeda’.”

7.59 billion years: The Earth and Moon are very likely destroyed by falling into the Sun, just before the Sun reaches the tip of its red giant phase and its maximum radius of 256 times the present-day value. Before the final collision, the Moon possibly spirals below Earth’s Roche limit, breaking into a ring of debris, most of which falls to the Earth’s surface.

100 billion years: “The Universe’s expansion causes all galaxies beyond the Milky Way’s Local Group to disappear beyond the cosmic light horizon, removing them from the observable universe.”

A tour of our solar system’s eclipses

posted by Jason Kottke   Aug 16, 2017

In a meditative video for the NY Times, Dennis Overbye takes us on a tour of eclipses that happen in our solar system and beyond.

On the 21st day of August, 2017, the moon will slide between the Earth and the sun, painting a swath of darkness across North America. The Great American Solar Eclipse. An exercise in cosmic geometry. A reminder that we live on one sphere among many, all moving to the laws of Kepler, Newton and Einstein.

Humans have many more vantage points from which to observe solar eclipses than when the last solar eclipse occurred in the US in 1979. I had no idea that the Mars rovers had caught partial solar eclipses on Mars…so cool. (via @jossfong)

Why is the upcoming total solar eclipse such a big deal?

posted by Jason Kottke   Jul 20, 2017

Well, the short answer is that they don’t happen all that often and when they do, they’ve visible from only a small bit of Earth. Joss Fong elaborates in a video for Vox.

The next total solar eclipse to visit the US will be in 2024. If an eclipse happens to come to your town, you’re lucky. Any given location will see a total solar eclipse only once in more than 300 years, on average. The vast majority of us will have to travel to an eclipse path if we want to see a total eclipse in our lifetimes.

I’m off to Nebraska in August to meet up with some friends and see the eclipse. (And that 2024 eclipse Fong mentions? The path of totality goes right over my damn house. Woooo!) But no matter where you are in North America, you can enjoy the eclipse…just make sure you buy some safety glasses (and other supplies) if you want to look directly at the Sun. (via @veganstraightedge)

How to safely enjoy the 2017 solar eclipse, a buyer’s guide for normal people

posted by Jason Kottke   Jul 12, 2017

Solar Eclipse Illo

Important update: Since I published this guide a month ago, NASA and the AAS have updated their recommendation on buying solar safety glasses due to reports of counterfeit eclipse glasses. They no longer recommend looking for the ISO rating alone but only buying from a recommended manufacturer. If you have purchased glasses or are going to purchase glasses, read this page carefully before using them, paying particular attention to this bit:

Unfortunately, you can’t check whether a filter meets the ISO standard yourself — doing so requires a specialized and expensive piece of laboratory equipment called a spectrophotometer that shines intense UV, visible, and IR light through the filter and measures how much gets through at each wavelength. Solar filter manufacturers send their products to specialized labs that are accredited to perform the tests necessary to verify compliance with the ISO 12312-2 safety specifications. Once they have the paperwork that documents their products as ISO-compliant, they can legitimately use the ISO logo on their products and packaging.

Even more unfortunately, unscrupulous vendors can grab the ISO logo off the internet and put it on their products and packaging even if their eclipse glasses or viewers haven’t been properly tested. This means that just seeing the ISO logo or a label claiming ISO 12312-2 certification isn’t good enough. You need to know that the product comes from a reputable manufacturer or one of their authorized dealers.

Amazon recently sent out emails to the buyers of the plastic-framed glasses I bought and linked to here (“habibee 4-Pack Black Plastic Eclipse Glasses CE & ISO Certified 2017 Safe Solar Eclipses Viewing Shades Block Sun Ultraviolet UV Lights Goggles”), saying that they have “not received confirmation from the supplier of your order that they sourced the item from a recommended manufacturer” and, to their credit, have automatically issued refunds to those buyers. They also appear to have removed any products from their site that aren’t sourced from a recommended manufacturer. This doesn’t necessarily mean the glasses are faulty…it just means the solar filter paper used for the lenses can’t be sourced. Again, read this page carefully before deciding to use any glasses you may have purchased. I tested a pair this morning, looking at bright light bulbs and they seem appropriately dark, but as noted by the AAS, who knows about the UV and IR filtering? I’m throwing mine out.

The cardboard-framed glasses I linked to (while currently sold out) are manufactured by American Paper Optics, which is on the AAS’s list of reputable vendors. Also on the list is the manufacturer of the solar filter sheets, Thousand Oaks Optical. The two cardboard camera lens covers I linked to have been deleted from Amazon, a sign that their sourcing cannot be verified. I’ve updated the links and text below to only include links to products on the list of reputable vendors. Most are sold out at this point anyway, so…

I wish I’d had these new NASA and AAS recommendations a month ago…I obviously would have followed them closely in making buying choices & recommendations. That some unscrupulous manufacturers are using people’s enthusiasm for science and viewing the eclipse to sell potentially harmful products makes me angry and sick to my stomach. Luckily Amazon is doing the right thing here with refunds and safety notices. And thanks to NASA and the AAS for their guidance…again please read this before using your eclipse glasses, even ones you may have gotten free from your public library or through other organizations. /end update

On August 21, 2017 across the entire United States, the Moon will move in front of the Sun, partially blocking it from our view. For those on the path of totality, the Moon will entirely block out the Sun for more than 2 minutes. I’ve been looking forward to seeing a total solar eclipse since I was a little kid, so I’ve been doing a lot of research on what to buy to enjoy the eclipse safely. Here’s what I’ve come up with.

I’ve oriented this guide toward the enthusiastic beginner, someone who’s excited about experiencing the wonder of the eclipse with their friends & family but isn’t interested in expensive specialty gear or photography (like me!). And, again, since you will be able to see this eclipse from everywhere in North America to some degree, this guide applies to anyone in the US/Canada/Mexico.

In planning for eclipse viewing, please check out NASA’s safety notes for more information. Make sure that whatever you buy, it’s properly rated for naked eye solar viewing. Looking directly at the Sun without a proper filter can cause permanent damage, particularly through binoculars, a camera lens, or a telescope.

Note: If you’re going to get eclipse supplies, now is the time. Some of this stuff will probably be very difficult to find (or very expensive) as we approach August 21 — for instance, shipping estimates on Amazon for some of the glasses are mid-August already.

Solar eclipse glasses are essential. Right up until the Sun goes completely behind the Moon (if you’re on the path of totality), you will want to look at the crescent-shaped Sun and you’ll need certified safety glasses to do so. Regular sunglasses will not work! Do not even. There are several options…find some in stock that ship soon. Note: If you have young kids, splurge for the plastic framed glasses (if you can find them…most are sold out now)…my testing indicates the cardboard ones don’t stay on smaller heads as well.

Make a pinhole viewer. A pinhole viewer will let you see the shape of the eclipsed Sun without having to look directly at it. This Exploratorium guide should get you started. All you need in terms of supplies you probably have lying around at home: aluminum foil, paper, cardboard, etc. I suspect Kelli Anderson’s This Book is a Camera ($27) might also work if you play with the exposure times?

Apply good sunscreen. You’ve got your eye protection down, now for the rest of yourself. The eclipse is happening in the middle of the day in much of the country, in what you hope will be complete sunshine, so bring some sunscreen. The Sweethome recommends this SPF 70 Coppertone for $9. Wear a cap. Stay in the shade. Bonus for shading yourself under trees: the gaps between the leaves will form little pinhole lenses and you’ll see really cool patterns:

Solar Eclipse Leaves

A nice pair of binoculars. If you’re in the path of totality, you might want a pair of binoculars to look more closely at the totally eclipsed Sun (after checking that it’s safe!!). I’m guessing you don’t want to buy a pair of specialty astronomy binoculars, so the best binoculars are probably ones you already own. If you don’t already have a pair, The Wirecutter recommends the Midas 8 x 42 binoculars by Athlon Optics ($290) with the Carson VP 8x42mm ($144) as a budget pick. (For solar filter options, see below.)

A solar filter for your camera. If you have a camera, they might make a solar filter for whatever lens you want to use. Hydrogen alpha filters will allow you to see the most detail — “crazy prominences and what-not” in the words of a photography pal of mine — but are also pretty expensive. You can buy solar filter sheets ($29) to make your own lens coverings for your camera, binoculars, or telescope. Quality will likely not be fantastic, but you’ll get something. Safety warning: place any filters in front of lenses or it can burn a hole in the filter (and then into your eye); i.e. don’t use binoculars in front of safety glasses!!

Note for budding solar photographers: Shooting the eclipse will be challenging. First there’s too much light and you’ll need a filter. Then when totality occurs, you’ll be in the dark needing a tripod and a fast lens. Plan accordingly…or leave it all at home and look at the thousands of photos taken by pro photographers after the fact.

Ok, that’s it. Have a good eclipse and stay safe!

Update: I removed a reference to the plastic-rimmed safety glasses I ordered because the image has changed on this item since I ordered them and published this guide…it’s now a wire-rimmed pair of glasses. I would recommend getting something else instead, just to be safe. (thx, @kahnnn)

Update: NASA has been alerted that some of the paper glasses being sold are not safe for viewing the eclipse. When buying, look for the ISO icon (referencing 12312-2) and for glasses made by these recommended manufacturers: American Paper Optics, Rainbow Symphony, Thousand Oaks Optical, or TSE 17. (via @ebellm)

Update: The Wirecutter has released their guide to The Best Solar Eclipse Glasses and Filters and they recommend the Celestron EclipSmart 2x Power Viewers (2-pack for $10), which provide not only certified eye protection but a nice 2X zoom.

Decoding the geometry, geology, and astronomy of Stonehenge

posted by Jason Kottke   Jun 28, 2017

Vox’s Joss Fong assembles a scale model of Stonehenge and explains some of the ancient monument’s geometry, the geology of the stone it’s built from, and the its possible astronomical significance.

Stonehenge is a popular destination for summer solstice celebrations because the 5,000-year-old monument points toward the summer solstice sunrise on the horizon. However, it also points to the winter solstice sunset in the opposite direction and there’s good reason to believe that this may have been the more important alignment for the Neolithic people who built Stonehenge. We investigate by constructing a tiny model of the Stonehenge monument.

NASA’s super accurate map of the 2017 eclipse

posted by Jason Kottke   Jun 14, 2017

Using data about the Moon’s terrain from the Lunar Reconnaissance Orbiter as well as elevation data on Earth, NASA’s Ernie Wright created a very accurate map of where and when the August 2017 eclipse will occur in the United States.

Standing at the edge of the moon’s shadow, or umbra, the difference between seeing a total eclipse and a partial eclipse comes down to elevation — mountains and valleys both on Earth and on the moon — which affect where the shadow lands. In this visualization, data from NASA’s Lunar Reconnaissance Orbiter account for the moon’s terrain that creates a jagged edge on its shadow. This data is then combined with elevation data on Earth as well as information on the sun angle to create the most accurate map of the eclipse path to date.

You can download maps of your area from NASA’s official eclipse website…I will be studying the Nebraska map closely.

Nebraska Eclipse Map

See also Eclipse Megamovie 2017, an eclipse simulator you can use to check what the eclipse will look like in the sky in your area, and what looks like an amazing eclipse watching festival put on by Atlas Obscura.

Vivid new images and flyby videos of Jupiter

posted by Jason Kottke   May 30, 2017

Jupiter South Pole Juno

NASA’s Juno spacecraft is currently orbiting around Jupiter and taking some of the best photos and scientific measurements we’ve seen of the solar system’s largest planet. The photo above is of Jupiter’s south pole, gathering point for massive cyclones.

Early science results from NASA’s Juno mission to Jupiter portray the largest planet in our solar system as a complex, gigantic, turbulent world, with Earth-sized polar cyclones, plunging storm systems that travel deep into the heart of the gas giant, and a mammoth, lumpy magnetic field that may indicate it was generated closer to the planet’s surface than previously thought.

“We are excited to share these early discoveries, which help us better understand what makes Jupiter so fascinating,” said Diane Brown, Juno program executive at NASA Headquarters in Washington. “It was a long trip to get to Jupiter, but these first results already demonstrate it was well worth the journey.”

Using data and photos from Juno, Gerald Eichstädt and Seán Doran have created these videos that approximate what it might look like flying by Jupiter in a spacecraft.

Wonderful.

What will the night sky look like in 5 million years?

posted by Jason Kottke   Apr 13, 2017

Based on the motions of the 2 million stars observed by ESA’s Gaia mission over the past two years, scientists created this simulated animation of how the view of the Milky Way in the night sky will evolve over the next 5 million years.

The shape of the Orion constellation can be spotted towards the right edge of the frame, just below the Galactic Plane, at the beginning of the video. As the sequence proceeds, the familiar shape of this constellation (and others) evolves into a new pattern. Two stellar clusters — groups of stars that were born together and consequently move together — can be seen towards the left edge of the frame: these are the alpha Persei (Per OB3) and Pleiades open clusters.

Stars seem to move with a wide range of velocities in this video, with stars in the Galactic Plane moving quite slow and faster ones appearing over the entire frame. This is a perspective effect: most of the stars we see in the plane are much farther from us, and thus seem to be moving slower than the nearby stars, which are visible across the entire sky.

Well, how’s that for some perspective? (via blastr)

The Orion Nebula, our friendly neighborhood star factory

posted by Jason Kottke   Apr 03, 2017

Orion Nebula

Rolf Olsen recently took this amazing photo of the Orion Nebula using a home-built telescope.

The Orion Nebula is one of the most studied objects in the sky and also has a significant place in the history of astrophotography. In 1880 it was the first ever nebula to be photographed; Henry Draper used the newly invented dry plate process to acquire a 51-minute exposure of the nebula with an 11 inch telescope. Subsequently, in 1883, amateur astronomer Andrew Ainslie Common recorded several exposures up to 60 minutes long with a much larger 36-inch telescope, and showed for the first time that photography could reveal stars and details fainter than those visible to the human eye.

Thanks to Phil Plait for the link…he’s got much more to say about the image and the nebula here.

Also called M42 (the 42nd object in a catalog kept by comet hunter Charles Messier in the late 18th century), it is a sprawling star factory, a gas cloud where stars are born. It’s a couple of dozen light-years across, and sits well over a thousand light-years from Earth. That’s 10,000 trillion kilometers, and you can see it with your naked eye! It’s so bright because of a handful of extremely massive hot stars sit in its center. They blast out ultraviolet light that energizes the gas in the nebula, causing it to glow.

It’s actually a small section of a much larger dark cloud, what’s called a molecular cloud, that we cannot see directly. Stars were born near the edge of that cloud, not too deeply inside it, and when they switched on their fierce light and stellar winds blew a hole in the cloud, popping it like a bubble. The Orion Nebula is a cavity in the side of that cloud, carved by the newborn stars.

A full rotation of the Moon

posted by Jason Kottke   Mar 31, 2017

All but a few humans have seen no more than half of the Moon with their own eyes. For the rest of us stuck on Earth, we only get to see the side that always faces the Earth because the Earth & Moon are tidally locked; the Moon’s rotation about its axis and its orbit around the Earth take the same amount of time. But NASA’s LRO probe has taken high-resolution photos of all but 2% of the Moon’s surface, which have been stitched together into this video of the Moon’s full 360-degree rotation.

A fictional flight above real Mars

posted by Jason Kottke   Mar 15, 2017

Using real images of Mars taken by the HiRISE camera on the Mars Reconnaissance Orbiter, Jan Fröjdman created a 3D-rendered flyover of several areas of the planet’s surface.

In this film I have chosen some locations and processed the images into panning video clips. There is a feeling that you are flying above Mars looking down watching interesting locations on the planet. And there are really great places on Mars! I would love to see images taken by a landscape photographer on Mars, especially from the polar regions. But I’m afraid I won’t see that kind of images during my lifetime.

It has really been time-consuming making these panning clips. In my 3D-process I have manually hand-picked reference points on the anaglyph image pairs. For this film I have chosen more than 33.000 reference points! It took me 3 months of calendar time working with the project every now and then.

Watch this in the highest def you can muster…gorgeous.

The Goddesses of Venus

posted by Jason Kottke   Mar 08, 2017

Goddesses Of Venus Map

Last year, Eleanor Lutz made a medieval-style map of Mars. As a follow-up, she’s made a topographical map of Venus. The features on Venus are named for female mythological figures & notable women and Lutz provides a small biography for each one on the map. Among those featured on the map are:

Anne Frank
Selu (Cherokee Corn Goddess)
Kali (Hindu Goddess, Mother of Death)
Virginia Woolf
Sedna (Eskimo Whose Fingers Became Seals and Whales)
Ubastet (Egyptian Cat Goddess)
Beatrix Potter
Edith Piaf

Here are the full lists of the craters, mountains, and coronae on Venus.

An appreciation of the Hubble’s Deep Field images

posted by Jason Kottke   Mar 03, 2017

More than 20 years ago, the Hubble Space Telescope took a photo of a patch of seemingly dark sky and, lo, it was filled with hundreds and hundreds of galaxies.

Hubble Ultra Deep Field

About ten years after that, they looked even deeper into the night sky and observed thousands of galaxies, each containing hundreds of billions of stars. The video above is an appreciation of these Deep Field images and what they taught us about the Universe.

In 1995, scientists pointed the Hubble Telescope at an area of the sky near the Big Dipper. The location was apparently empty, and the whole endeavour was risky — what, if anything, was going to show up? But what came back was nothing short of spectacular: an image of over 1,500 galaxies glimmering in a tiny sliver of the universe. Alex Hofeldt helps us understand the scale of this image.

NASA has found 7 Earth-like planets orbiting a single nearby star

posted by Jason Kottke   Feb 22, 2017

Trappist 1

Today NASA announced the discovery of seven planets “that could harbor life” around a dwarf star called Trappist-1.

The planets orbit a dwarf star named Trappist-1, about 40 light years, or about 235 trillion miles, from Earth. That is quite close, and by happy accident, the orientation of the orbits of the seven planets allows them to be studied in great detail.

One or more of the exoplanets - planets around stars other than the sun - in this new system could be at the right temperature to be awash in oceans of water, astronomers said, based on the distance of the planets from the dwarf star.

“This is the first time so many planets of this kind are found around the same star,” said Michael Gillon, an astronomer at the University of Liege in Belgium and the leader of an international team that has been observing Trappist-1.

Here’s the paper published in Nature.

The leisurely pace of light speed

posted by Jason Kottke   Jan 25, 2017

In a 45-minute video called Riding Light, Alphonse Swinehart animates the journey outward from the Sun to Jupiter from the perspective of a photon of light. The video underscores just how slow light is in comparison to the vast distances it has to cover, even within our own solar system. Light takes 8.5 minutes to travel from the Sun to the Earth, almost 45 minutes to Jupiter, more than 4 years to the nearest star, 100,000 years to the center of our galaxy, 2.5 million years to the nearest large galaxy (Andromeda), and 32 billion years to reach the most remote galaxy ever observed.1 The music is by Steve Reich (Music for 18 Musicians), whose music can also seem sort of endless.

If you’re impatient, you can watch this 3-minute version, sped up by 15 times:

  1. This isn’t strictly true. As I understand it, a photon that just left the Sun will never reach that most remote galaxy.

A beautiful aquarium supernova

posted by Jason Kottke   Jan 04, 2017

Using mostly old-school visual effects — like ink dispersing in an aquarium and poking holes in napkins (to represent stars) — Thomas Vanz created a pretty compelling representation of a dying star going supernova.

Novae is a movie about an astronomical event that occurs during the last evolutionary stages of a massive star’s life, whose dramatic and catastrophic death is marked by one final titanic explosion called supernova.

By only using an aquarium, ink and water, this film is also an attempt to represent the giant with the small without any computed generated imagery.

As a tribute to Kubrick or Nolan’s filmography, Novae is a cosmic poem that want to introduce the viewer to the nebulae’s infinite beauty.

Vanz documented his process in these two videos, which are almost as entertaining as the finished product.

The Universe has 10 times more galaxies than we thought

posted by Jason Kottke   Oct 17, 2016

Hubble Ultra Deep Field

A recent paper claims that the Universe has 10 times more galaxies than we previously thought: an estimated 2 trillion galaxies covering every single patch of sky visible from the Earth. But that doesn’t mean the Universe is more massive or that it contains more stars. Phil Plait explains:

Now, let me be clear. This doesn’t meant the Universe is ten times bigger than we thought, or there are ten times as many stars. I’ll explain — I mean, duh, it’s what I do — but to cut to the chase, what they found is that there are lots of teeny, faint galaxies very far away that have gone undetected. So instead of being in a smaller number of big galaxies, stars are divvied up into a bigger number of smaller ones.

So how many stars are there in the Universe? The Milky Way contains about 400 billion stars. Some massive elliptical galaxies house more than 100 trillion stars. Estimates of the total number are rough, but it’s probably around 10^24 stars…that’s a septillion stars, a trillion trillion. It’s absurd that we’d be the only planet in the Universe with life on it.

Possible Earth-like planet discovered orbiting star nearest Earth

posted by Jason Kottke   Aug 19, 2016

Exoplanet Art

The scientific rumor mill is saying that astronomers in Chile have discovered an Earth-like exoplanet orbiting the star nearest Earth, Alpha Proxima, a mere 4.25 light years away. As they say, “huge if true”.

The hunt for exoplanets has been heating up in recent years. Since it began its mission in 2009, over four thousand exoplanet candidates have been discovered by the Kepler mission, several hundred of which have been confirmed to be “Earth-like” (i.e. terrestrial). And of these, some 216 planets have been shown to be both terrestrial and located within their parent star’s habitable zone (aka. “Goldilocks zone”).

But in what may prove to be the most exciting find to date, the German weekly Der Spiegel announced recently that astronomers have discovered an Earth-like planet orbiting Proxima Centauri, just 4.25 light-years away. Yes, in what is an apparent trifecta, this newly-discovered exoplanet is Earth-like, orbits within its sun’s habitable zone, and is within our reach. But is this too good to be true?

If you read the article, there’s cause for skepticism but an official announcement is coming next week so we’ll know for sure one way or the other.

The other cool thing? If there is a planet there, plans are already underway to build a project to get probes to nearby Alpha Centuri in 20 years, Project Starshot:

In the last decade and a half, rapid technological advances have opened up the possibility of light-powered space travel at a significant fraction of light speed. This involves a ground-based light beamer pushing ultra-light nanocrafts - miniature space probes attached to lightsails - to speeds of up to 100 million miles an hour. Such a system would allow a flyby mission to reach Alpha Centauri in just over 20 years from launch, and beam home images of possible planets, as well as other scientific data such as analysis of magnetic fields.

Perhaps they can redirect their target slightly?

Update: It appears as if the rumors were true. Phil Plait writing at Slate:

The planet, called Proxima Centauri b or just Proxima b (exoplanets are given their star’s name plus a lower case letter in order of discovery, starting with “b”), orbits Proxima every 11.2 days. It has a mass of no less than 1.3 times the Earth’s, so if it’s rock and metal like Earth it’s only a bit bigger. It’s a mere 7.3 million kilometers from the star-a lot closer than Earth’s distance from the Sun of 150 million kilometers!-but Proxima is so faint and cool it receives about two-thirds the amount of light and heat the Earth does. That means that it’s in Proxima’s habitable zone: It’s possible (more or less) that liquid water could exist on its surface.

That’s coooool.

Update: Project Blue wants to built a space telescope for the purpose of observing and photographing Earth-like planets around Alpha Centuri.

Project Blue is a consortium of leading space and research organizations on a mission to build and launch a small space telescope to observe planets around our nearest stellar neighbors: Alpha Centauri A and B. The goal is simple: to capture an image, visible to the human eye, of orbiting planets. Seeing a “pale blue dot” could indicate the presence of oceans or an atmosphere — the potential to support life. It would be our first view of another world like our own. With a modest budget and a planned launch by 2020, this goal is tantalizingly close.

The Perseid meteor shower should be great this year

posted by Jason Kottke   Aug 08, 2016

Perseids

Every year, the Earth moves through the debris from the Swift-Tuttle comet, resulting in the Perseid meteor shower. This year, the Earth is predicted to move through a particularly dense part of the comet’s wake, which may mean twice the number of shooting stars during this year’s shower. Here’s how to watch:

The best way to see the Perseids is to go outside between midnight and dawn on the morning of Aug. 12. Allow about 45 minutes for your eyes to adjust to the dark. Lie on your back and look straight up. Increased activity may also be seen on Aug. 12-13.

I always find these directions confusing, so to be clear: the best viewing for the Perseids is the night of Aug 11 (Thu) into the morning of Aug 12 (Fri). Good luck!

A year-long time lapse of the Earth rotating in space

posted by Jason Kottke   Jul 22, 2016

NASA recently released a time lapse video of the Earth constructed from over 3000 still photographs taken over the course of a year. The photos were taken by a camera mounted on the NOAA’s DSCOVR satellite, which is perched above the Earth at Lagrange point 1.

Wait, have we talked about Lagrange points yet? Lagrange points are positions in space where the gravity of the Sun and the Earth (or between any two large things) cancel each other out. The Sun and the Earth pull equally on objects at these five points.

L1 is about a million miles from Earth directly between the Sun and Earth and anything that is placed there will hover there relative to the Earth forever (course adjustments for complicated reasons aside). It is the perfect spot for a weather satellite with a cool camera to hang out, taking photos of a never-dark Earth. In addition to DSCOVR, at least five other spacecraft have been positioned at L1.

L2 is about a million miles from the Earth directly opposite L1. The Earth always looks dark from there and it’s mostly shielded from solar radiation. Five spacecraft have lived at L2 and several more are planned, including the sequel to the Hubble Space Telescope. Turns out that the shadow of the Earth is a good place to put a telescope.

L3 is opposite the Earth from the Sun, the 6 o’clock to the Earth’s high noon. This point is less stable than the other points because the Earth’s gravitational influence is very small and other bodies (like Venus) periodically pass near enough to yank whatever’s there out, like George Clooney strolling through a country club dining room during date night.

And quoting Wikipedia, “the L4 and L5 points lie at the third corners of the two equilateral triangles in the plane of orbit whose common base is the line between the centers of the [Earth and Sun]”. No spacecraft have ever visited these points, but they are home to some interplanetary dust and asteroid 2010 TK7, which orbits around L4. Cool! (via slate)

NASA extends the missions of nine spacecraft

posted by Jason Kottke   Jul 05, 2016

While we’re on the subject, NASA announced late last week that they are extending the missions of nine spacecraft sprinkled about the solar system. Included are the New Horizon probe, which will wing off to study an object in the Kuiper Belt after doing so well with Pluto and the rover Opportunity, which was slated for a mission lasting just over 90 days but has now spent more than 12 years exploring the surface of Mars.

The Dawn mission to Ceres is another spacecraft whose duration has been extended, beating long odds. Part of the spacecraft’s functionality had not been working for some time, but was recently repaired.

It was a bit unexpected because Dawn is low on fuel. “Less than a year ago, I would have thought it was ridiculous that the spacecraft would even be operating at this point,” said Marc D. Rayman, the chief engineer for the Dawn mission.

The Dawn spacecraft was designed to use four spinning wheels to pivot in different directions. But at its previous destination, the asteroid Vesta, two of the four wheels overheated and failed. At Ceres, the wheels stayed off, and the spacecraft used its thrusters instead to pivot.

In December, Dawn reached its lowest orbit, just 240 miles above Ceres. Dr. Rayman said he and his team had expected Dawn to exhaust its remaining propellant by March.

But they spun up the wheels again. That succeeded, cutting the use of the thrusters. “It all worked out beautifully,” Dr. Rayman said. That left enough fuel to contemplate doing something more.

Juno successfully enters orbit around Jupiter

posted by Jason Kottke   Jul 05, 2016

After a voyage from Earth lasting almost 5 years, the Juno spacecraft successfully entered Jupiter’s orbit late last night.

The engine burn was tense. 35 minutes is a long time for a spacecraft burn; after 20 minutes it had slowed Juno enough to be in orbit, but not the correct one. It had to continue for another 15 minutes to put the spacecraft on the correct orbit. It worked essentially perfectly. The burn time was off by just one second. That will have no real effect on the orbit.

The 35-minute burn slowed Juno down by more than 1200 mph.

NASA’s Juno mission to Jupiter

posted by Jason Kottke   Jun 28, 2016

Launched from Earth in August 2011, the Juno probe is due to arrive at Jupiter on July 4, 2016. Once there, it will circle Jupiter 37 times, observing its atmosphere and magnetic fields, before plunging into the giant planet so as not to contaminate Europa with microbes.

Juno’s principal goal is to understand the origin and evolution of Jupiter. Underneath its dense cloud cover, Jupiter safeguards secrets to the fundamental processes and conditions that governed our solar system during its formation. As our primary example of a giant planet, Jupiter can also provide critical knowledge for understanding the planetary systems being discovered around other stars.

With its suite of science instruments, Juno will investigate the existence of a solid planetary core, map Jupiter’s intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet’s auroras.

Juno will let us take a giant step forward in our understanding of how giant planets form and the role these titans played in putting together the rest of the solar system.

Science is great. That video? Maybe not so much.

Gravity is the new light

posted by Tim Carmody   Jun 16, 2016

Gravitational waves from two colliding black holes were first detected last September and announced in February. This week, the same science team announced a second wave detection of two smaller black holes in December.

If the first one confirmed the long-held predictions of general relativity, the new detections are a signal to get started on some all-new science.

A black hole’s gravity is so strong that even light can’t escape, so black holes are essentially impossible to see with telescopes. But they do give off gravitational waves.

“Light’s always been how we do astronomy,” Professor Jo Dunkley, an astrophysicist at Oxford University who didn’t work on the experiment, told BuzzFeed News. “Everything we know about space, we’ve got from light. This can show the stuff you can’t see with light.”

Counting black holes, combining telescope with gravitational measurements to better understand neutron stars, all the usual origin-of-the-universe stuff.

If gravitational waves don’t require cataclysmic collisions between enormous black holes for us to measure them, but can be detected on the regular, we can use them to try to figure out a whole lot more than just whether or not Einstein was totally right. That is a very nice tool to have in your pocket.

The legally blind astronomer

posted by Jason Kottke   Jun 06, 2016

Tim Doucette is a legally blind astronomer. A pair of surgeries when he was younger to help improve his vision left him with a superpower: because his pupils were permanently dilated, he could see in the dark better than other people. He built an observatory and with the aid of his telescope, he can see details of far-off stars and nebula that no one else can, including UV and infrared light.

What are the physical limits of humanity?

posted by Jason Kottke   May 12, 2016

A new video from Kurzgesagt explores the limits of human exploration in the Universe. How far can we venture? Are there limits? Turns out the answer is very much “yes”…with the important caveat “using our current understanding of physics”, which may someday provide a loophole (or wormhole, if you will). Chances are, humans will only be able to explore 0.00000000001% of the observable Universe.

This video is particularly interesting and packed with information, even by Kurzgesagt’s standards. The explanation of the Big Bang, inflation, dark matter, and expansion is concise and informative…the idea that the Universe is slowly erasing its own memory is fascinating.

Epic time lapse videos of Mercury’s transit of the Sun

posted by Jason Kottke   May 10, 2016

About 13 times per century, the planets align in the heavens and the Earth can watch Mercury crossing the face of the Sun. NASA’s Solar Dynamics Observatory was watching too and captured time lapse videos from several angles using various instruments measuring magnetism, visible light, and UV. The cosmic ballet goes on.

See also more from the SDO: a gorgeous time lapse of the Sun, a three-year video portrait of the Sun, and Thermonuclear Art.