Deployment of Webb Space Telescope’s mirror’s successful, but we’re not there yet

January 20, 2022 • 11:00 am

The toughest bit, though seems past: successfully unfolding the entire mirror of the Webb Space Telescope was the most delicate of all its operations, since nothing could fail without endangering the scope’s usefulness. And nothing did! NASA has reported, along with many other sites, that the main mirror deployment is, as they say, “nominal.”  From

JWST’s golden primary mirror includes 18 individual hexagonal segments, each controlled by seven actuators that allow precise movements. All 18 segments are now in their deployed positions several days sooner than scheduled.

Work began on the mirror segments on Jan. 12 and was expected to take about 10 days. But despite today’s announcement, those mirror segments aren’t quite ready to observe yet. First, NASA must conduct the painstaking process of fine-tuning every mirror’s position to turn 18 individual views of the universe into one large ultra-powerful mirror.

The team behind Webb expects that the entire mirror process will take about three months, all told.

Here’s a NASA video of the immensely complicated process of aligning all the mirrors once they’ve unfolded. I have faith in the Telescope Humans that all will be well.


If this works okay, and nothing else goes wrong, in a few months the scope will be in position and ready to send data. There is one more important maneuver:

Webb has one more key deployment milestone to complete, a trajectory burn that will insert the observatory into orbit around a spot in space dubbed the Earth-sun Lagrange point 2, or L2. L2 is located nearly 1 million miles (1.5 million kilometers) away from Earth, on the side of the planet opposite the sun.

According to a NASA timeline, JWST is expected to complete this final arrival maneuver on Sunday (Jan. 23).

A good site to follow is “Where is Webb?” NASA’s real-time timeline of the mission showing the location of the scope and what it’s doing. Below is a screenshot that you can click on to see where Webb is now. It’s approaching “L2 insertion” on the right! Click on the photo to enlarge it.


Wake up! Space telescope to be launched today at 7:20 Eastern time.

December 25, 2021 • 5:00 am

MERRY CHRISTMAS!  Here’s a present to the world from science—international science.

I know people are up in Europe, and if you’re an early riser in America, you’ll want to see this too (the Kiwis and Aussies will be asleep unless they’re night owls). The James Webb Space Telescope will be launched today, on Christmas Day, at 7:20 Eastern U.S. time, or 6:20 Chicago time. I’m already up at 4:30 to do my ablutions and have coffee before the big takeoff. The good news is that many Americans will be forced to be awake by early-rising kids who want to open their presents.

When this is posted it will be 6 a.m. Eastern U.S. time: 1 hour and 20 minutes to go! And the NASA feed below will have begun.

You know what’s happening: the space telescope, far more powerful than the Hubble, will provide oodles of scientific information, including detecting infrared light from billions of years ago. You can read about it at Wikipedia, or at the NASA site

Here’s the NASA live feed:

Fingers crossed!

A feed from the NASA site that does have commentary (click on screenshot to go to NASA t.v.):

And another live feed:

I believe all conditions are go (things are “nominal”, as they say), and only weather or one other thing could mess up the launch (xkcd cartoon courtesy of Matthew):

James Webb Space Telescope

December 20, 2021 • 11:30 am

On Wednesday, as the 13-minute “60 Minutes” segment below explains, the $10-billion-dollar James Webb Space Telescope will be launched.  Thirty days later, it will be nearly a million miles from Earth, in orbit around the Sun.

One of its goals is to detect leftover radiation traveling over billions of light years, giving us a glimpse of the past and, perhaps, into what “dark matter” is.  But, as you’ll see, it can also answer many other questions.

If you want to read more than you’ve absorbed from this segment, go to either the Wikipedia page or on the telescope’s NASA site.

I’m continuslly stunned by what humans can do with simple materials extracted from the Earth. And it’s great that this effort involves international cooperation.

h/t: Nicole

A near total lunar eclipse tonight

November 18, 2021 • 11:00 am

If you’re a night owl, you’ll want to watch the Moon tonight, especially around 1:00 a.m Eastern U.S. time, for there will be a rare near-total lunar eclipse of a full moon. Set your alarms now (I’ll be sleeping). (here and here) reports the event and tells you how to watch it online if there are too many clouds in your area. It’s not only a big eclipse, with the Earth’s shadow covering 97% of the visible Moon, but also a LONG one: almost exactly 6 hours long. It’s also the longest partial lunar eclipse in 6 centuries!:

It will be the second lunar eclipse of 2021 and, in some ways, will be similar to the last one on May 26. Most North Americans will again need to get up early and look low in the west toward daybreak. And again, the farther west you are the better, as the moon will appear much higher from the western part of the continent as opposed to locations farther to the east. It will also be the longest partial lunar eclipse in 580 years, lasting just over 6 hours, with its pass through the darkest part of Earth’s shadow taking about 3 hours, 28 minutes and 23 seconds, and also the longest this century.

Here’s where it will be visible, including all the U.S., Canada, Central America, western South America, and Eastern Asia:

And a U.S. chart of the various phases:

If it’s clear, I’ll get to see the tail end as I walk to work.

You may be wondering why they call this the “Beaver Moon” eclipse. The Washington Post says this:

At the time of the eclipse, the moon will be full. Some refer to the November full moon as the “beaver moon,” a name assigned by Native Americans when beavers were particularly active in preparation for winter and it was time to set traps, according to NASA.

If you want to watch it online, here are four sites:

The Griffith Observatory in Los Angeleswill feature a timelapse video of the eclipse, weather permitting, on its YouTube page. The timelapse will start at 9 a.m. EST (1400 GMT/6 a.m. PST), with an online broadcast beginning before that on Friday, Nov. 19 at 1 a.m. EST (0600 GMT/ 10 p.m. PST on Nov. 18).

Time and Date will start its livestream on YouTube at 1 a.m. EDT (0600 GMT) on YouTube.

The Virtual Telescope Project will broadcast live from Rome starting at 2 a.m. EDT (0700 GMT).

The Astronomical Society of South Australiawill have broadcasts on YouTube or Facebook starting at 4:30 a.m. EST (0930 GMT or 7 p.m. local time).

And here’s an idea of how it will look (it won’t become invisible, just orange):

h/t Ginger K.

The Sun throws up

November 5, 2021 • 2:45 pm

Here’s a lovely NASA video a solar flare imaged several different ways, though I’m not fond of the music. Read the link in the preceding sentence to see how they’re caused.

On August 31, 2012 a long filament of solar material that had been hovering in the sun’s atmosphere, the corona, erupted out into space at 4:36 p.m. EDT. The coronal mass ejection, or CME, traveled away from the sun at over 900 miles per second. This movie shows the ejection from a variety of viewpoints as captured by NASA’s Solar Dynamics Observatory (SDO), NASA’s Solar Terrestrial Relations Observatory (STEREO), and the joint ESA/NASA Solar Heliospheric Observatory (SOHO).

And here’s a “cannibal coronal mass” from just three days ago: one ejection eats up another one. These things can cause spectacular auroras on Earth.

h/t: Rick

Readers’ wildlife photos

October 30, 2021 • 8:00 am

Today we have three photos and some science from Lou Jost, a polymath biologist who works at a field station in Ecuador. His notes are indented, and you can click on the photos to enlarge them.

Recently I gave Jerry some photos of plant fluorescence, which is visible light excited by incoming UV light. The fluorescent light is just normal light that you can see with the unaided eye, but the UV light I used to excite the fluorescence is invisible, with wavelengths too short to be detected  by our eyes. There is also invisible light on the other side of the visible-light spectrum, beyond the long red wavelengths. This is infrared light. Though we can’t see it, camera sensors are quite sensitive to it. Camera makers have to build their cameras with infrared-blocking filters in front of their sensors, so that colors look the same as what our eyes see. These filters can be removed. The camera that I used to take today’s pictures has had this surgery.

The first picture shows a rocky mountain in front of my house, covered in evergreen tropical forest. The forest is red because it is reflecting lots of infrared light, which the camera is reading as red.  Things that don’t reflect much infrared (the rocks and sky) have their normal colors.  This is actually a composite of two images, one with a filter that cuts out infrared light and the other with a filter that cuts out visible light (and then converting the resulting monochrome image to a red one). The two images are overlaid on top of each other and at each pixel, I keep the brightest one. This view is how the world would look if our red cones had a slightly extended spectral response.

The next picture is the volcano next to my house. It is a single photo, taken with an “IR Chrome” filter which gives a result similar to the two-photo method I used in the first photo. The vegetation along the flank of the volcano glows red.

The picture of my night sky is taken without any filter; it is white-balanced to visible light but it is sensitive to infrared too. The universe emits lots of infrared radiation, so an infrared -sensitive camera is much more effective for astrophotography than a normal consumer camera. Here you can see the Milky Way, with a brilliant magenta nebula in the middle. This is the Lagoon Nebula, a particularly beautiful celestial object. It is three or four times bigger across the sky than the moon! But just barely visible to the naked eye if you are lucky.

Readers’ wildlife photos

August 21, 2021 • 8:00 am

PLEASE send in your wildlife photos, as I have only a few days’ worth before I run out. You wouldn’t want that to happen, do you? Please make sure they’re good pics, of the quality that we see on this feature.

Today we have a melange of photos from several readers. Their captions are indented and you can enlarge their photos by clicking on them.

First, a yellow garden spider from Killian Sharp:

Argiope aurantia was just relaxing in its web amongst my friend’s tomato plants in SW Ontario.

From Julia Sculthorpe:

I have been taking pictures of wildlife in the various wildlife refuges in the Denver metro area. These were taken in the Rocky Mountain Arsenal National Wildlife Refuge.

The dragonfly and toad blend into their surroundings. The toad was very hard to photograph as he jumped at  almost any moment I made.


Can you spot the toad and dragonfly (the insect is easier)?

From Laurie Berg:

Immature eagle with former mouse

From Rachel Sperling:

I was saving this photo for when I had more to share, but I saw your request this morning. I’m pretty sure this is a dark fishing spider (Dolomedes tenebrosus). I encountered it on the New York section of the Appalachian Trail earlier this month. In addition to insects (not sure what type of beetle this one has caught) larger ones are able to catch fish. According to Wikipedia, their bodies are covered with hydrophobic hairs that allow them to run on water (suck it, Jesus). When they submerge, the air trapped in these hairs becomes a thin film, allowing them to breathe underwater; the air makes them quite buoyant, so they have to hold onto a twig or a rock in order to stay submerged. I think they’re really cool.

Also sharing a photo I took last night of the ALMOST full strawberry moon. This is from a park in Meriden, Connecticut, which has a lovely ridge that offers views to the east and west. This was taken around 8:30.

Some science listening from the BBC

July 30, 2021 • 10:00 am

Reader Dom called my attention to today’s BBC Science in Action program, which contains several items of interest. You can hear the 35-minute show by clicking on the site below and clicking “listen now”:

There are four bits:

Start – 12:20.  A discussion with Elizabeth Turner about her new evidence for 890-million-year-old animals (spongelike creatures), which I wrote about yesterday.

12:20-18:55.  A discussion with Cambridge University’s Dr Sanna Cottaar about the “Insight” probe on Mars’s surface and scientists’ attempt to deduce the structure of the planet.

18:55-26:45: Prof Lesley Lyons from the University of Missouri discusses the similarity of the genome of cats to that of humans, and how that could be used for medical purposes in humans. I’m not keen on this because it implies that they’re going to experiment on cats. As she says, “they’re bigger than mice and cheaper than primates”.

26:45-end:  A remembrance of Steven Weinberg, who died a week ago. There are extracts from two BBC interviews with Weinberg as well as discussions of his work by fellow scientists.

Readers’ wildlife photos

July 29, 2021 • 8:00 am

Send in your photos!

Today’s batch comes from reader Mark Otten, whose captions are indented. You can enlarge his photos by clicking on them:

I have a bit of a mish-mash of photos taken in 2020 and 2021 for your consideration.


Brood X of the 17-year periodical cicadas [Magicicada sp.] emerged in my neighborhood this summer.  Here are two photos of a white-eyed male I came across in June.  The close up on the compound eye was taken through a stereoscopic dissecting microscope at 25X. [JAC: this is surely a mutation]

In Spring 2019, Union Township, Clermont County, Ohio stocked a local pond with 5 female and 5 male Mandarin ducks (Aix galericulata).  One male returned to the pond in early winter 2020, creating much excitement among enthusiasts in the area.  The two photos below were taken on December 10, 2020.  The photo of the duck floating was taken by my wife Dianne.

Comet C/2020 F3 (Neowise).  Photo taken on July 16, 2020.

Jupiter-Saturn conjunction.  Photo taken on December 21, 2020.

 Mars and open star cluster M-45 (The Pleiades).  Photo taken on March 7, 2021.


Readers’ wildlife photos

June 26, 2021 • 8:00 am

Please send in your good wildlife/street/travel photos, as I’m getting nervous again (or rather, I’m always nervous):

Today’s photos come from Matt Young, one of the founders of the excellent pro-evolution website Panda’s Thumb.  His notes and captions are indented, and you can enlarge his photos by clicking on them.


Pursuant to your request for nature photographs, here is a baker’s half-dozen that I sent to Science in honor of Nature Photography Day. I have some text that goes with them.

Additionally, could I interest you in announcing the 13th annual Panda’s Thumb Photography Contest, here?

For my 80th birthday, my son gathered some of my “favorite” pictures on some pretext or other, and presented me with a splendid casebound book, cleverly formatted with quotations, mostly by photographers. These are some of the pictures that I chose.

American avocet, Recurvirostra americana, Cottonwood Lake, Boulder, Colorado. This one was just standing there, begging to be photographed, as I biked past.

Orange meadowhawk, Sympetrum spp., Elmer’s Two-Mile Creek, Boulder, Colorado. Dragonflies are a dream to photograph, because they often return to roost in the same spot.

Rainbow Bridge,, Rainbow Bridge National Monument, Utah, just off Lake Powell.

Antelope Canyon, a slot canyon near Page, Arizona, on Navajo land. I took a guided tour (the only way you can see it) and was lucky to get a couple of halfway decent pictures despite the darkness and the guide always at my heels.

Crepuscular rays, Niwot, Colorado. In this picture, you can see clearly that the rays are formed by atmospheric scattering, where the irregularities in the clouds are essentially projected onto the atmosphere. Also, every cloud has a silver lining (sometimes gold).

Painted turtleChrysemys picta, Walden Ponds, Boulder, Colorado. This is the western variant, at roughly its westernmost extreme, yet you can see many of them sunning themselves in Duck Pond every year.

Eclipse of the sun, Jackson, Wyoming, August 21, 2017.

And, finally, a mite too late for the book, an eclipse of the moon, just before sunrise on May 28, 2021. The moon was not visible after totality because of the brightening sky and set soon after.