Category: astronomy and cosmology

A three-dimensional map of the Universe

July 28, 2020 • 1:45 pm

Well, I can’t say I fully understand what’s being shown here, except that it depicts the detectable galaxies in the Universe (some not seen because the Milky Way hides them).  Cosmos has an explanation that I put below the video. If you’re an astronomy buff, you’ll probably understand this, and I’m hoping the cosmology mavens in the crowd will explain in the comments what we’re seeing.

Here’s one video, and another is below:

An explanation from Cosmos:

Astrophysicists have created the largest and most complete 3D map of the Universe.

It includes measurements of more than two million galaxies and quasars covering 11 billion years of cosmic time and involved 20 years of watching the skies and subsequent analysis by an international collaboration of more than a hundred researchers.

It is based on the latest observations of the Sloan Digital Sky Survey (SDSS), titled the extended Baryon Oscillation Spectroscopic Survey (eBOSS). The results and data have been released in more than 20 scientific papers running to 500+ pages.

Prior to eBOSS, scientists only knew where objects such as galaxies and quasars were as viewed from Earth. The new survey provides the distance to each object, allowing them to build a 3D model.

And that adds significantly to our understanding of the expansion of the Universe.

“We know both the ancient history of the Universe and its recent expansion history fairly well, but there’s a troublesome gap in the middle 11 billion years,” says Kyle Dawson, from the University of Utah, US.

“For five years, we have worked to fill in that gap, and we are using that information to provide some of the most substantial advances in cosmology in the last decade.”

The map has been published as a still image and as a 3D animation (below). A close look at the image reveals the filaments and voids that define the structure in the Universe, the researchers say, starting from when it was only about 300,000 years old.

h/t: Barry

Readers’ wildlife photos

July 24, 2020 • 7:45 am

On this site, astronomy counts as “wildlife”, and readers Leo Glenn and Mark Jones sent some lovely pictures of Comet Neowise, which I haven’t been able to see. Leo and Mark’s words are indented; click photos to enlarge them.

First, photos from Leo:

While these technically aren’t wildlife photos (well, one might qualify), I thought your readers might enjoy these pictures I took of Comet Neowise, on the evening of July 21 from my front yard in western Pennsylvania. I am just a hobbyist photographer, and this was my first attempt at night sky photography. After some failed and frustrating efforts, I was able to get these photos, which turned out better than I expected. The hardest part was focusing the camera when I could see nothing in the viewfinder. I thought I could just set the focus at infinity, but when I did that the photos were blurry. In the end, I pointed the camera at the brightest object, which happened to be Jupiter, and was able to get an acceptable (though not perfect) focus. For those interested, I used a Nikon D7100 DSLR with a 35 mm lens, at f-1.8 and a 30-second exposure. I forgot to set the ISO, so the camera did that automatically, which was a mistake, but I was able to correct for it later in Photoshop. And I used the timer so my finger on the shutter release wouldn’t blur the photo.

The red line is an airplane. I didn’t notice it until after I pressed the shutter release.

Eventually, clouds started to roll in, but that also provided some interesting photo opportunities. This is the only photo that might qualify as a wildlife photo. You can see a couple fireflies (Photinus and/or Photuris sp.), one on the left zooming rather close to the camera, and one at the bottom of the photograph toward the right,  just over the top of a tree.

Finally, I couldn’t resist pointing the camera up to take a picture of the starry sky, and was stunned by how many stars, invisible to the naked eye, appeared in the photo. I couldn’t help hearing Bill Shatner’s voice: “Space. The final frontier.”
Two photos from Mark Jones, who says:

You may want to add these to the pile of Neowise photos; it becomes rather compulsive to try to capture this excellent ‘omen’ for posterity, even though many have already!

One is taken from my kitchen window, and the other shows the comet above the house from the driveway.

Readers’ wildlife photos

May 23, 2020 • 7:45 am

Today we have a story by reader Kurt Helf about which he called “Honeybee rescue in the time of Covid-19”,  and also a lovely astronomical photograph by Tim Anderson. First, Kurt’s story; his words are indented:

To break up the teleworking workday I take regular midday walks around the neighborhood.  Two weeks ago I noticed a dark, football sized mass on one of the flowering trees lining a neighbor’s driveway:
It was a swarm of honeybees (Apis mellifera) likely on their penultimate stop before finding a permanent residence. I didn’t think the homeowner, who is a single, older man and a bit of a recluse, had noticed the swarm yet. However, I was afraid that when he did notice them they would be destroyed. I know a couple of local Apiarists so I asked them, given the homeowner was willing, if they would come get the bees. I went to talk to the homeowner, rang his doorbell, and stepped back a couple meters to give him space. However, he was unwilling to even open the door. I left, dejected, thinking the swarm was likely doomed. However, as I walked by the next day I saw the following:

Apparently, the homeowner had noticed the swarm, called the state, and was referred to a local apiarist who came to collect the swarm. Nice fella despite being surrounded by a cloud of bees. Later that day I rode my bike through the neighborhood and noticed that, while the apiarist was gone, he had left the hive box behind.

He put the queen and all the bees he could collect into the little hive but left it behind so the scouts would have a chance to return at the end of the day.  While my assumption regarding my neighbor’s willingness to destroy a swarm of honeybees was wrong I *would* go through the same machinations again (is that evidence for determinism?) because you never know what people will do.  Anyway, a happy ending in gloomy times!

And from reader Tim Anderson in Australia, a CAT NEBULA, and sure enough, it resemble a cat paw:

This feline apparition is NGC6334, known as the Cat’s Paw Nebula—an emission nebula in the Scorpius constellation. John Herschel first observed it from South Africa in 1837.

New telescope visualizes roiling cells of plasma at the Sun’s surface

February 5, 2020 • 1:30 pm

Reader Mark called my attention to these new videos from the Daniel K. Inouye solar telescope, a four-meter scope near the summit of Haleakala, Maui, in Hawai‘i (you can read about it at the National Science Foundation’s site here). It’s taken some stunning pictures of the Sun’s surface, including giant roiling cells of plasma shown in the “video” below, which appears to be time-lapse photography, but is no less impressive because of that. The NSF site notes this:

The first images from NSF’s Inouye Solar Telescope show a close-up view of the Sun’s surface, which can provide important detail for scientists. The images show a pattern of turbulent “boiling” plasma that covers the entire Sun. The cell-like structures — each about the size of Texas — are the signature of violent motions that transport heat from the inside of the Sun to its surface. That hot solar plasma rises in the bright centers of “cells,” cools off and then sinks below the surface in dark lanes in a process known as convection. (See video available with this news release.)

And the video, by SciNews, adds this:

The first movie covers an area of 36,500 x 36,500 km (22,600 x 22,600 miles, 51 x 51 arcseconds), while the second one covers an area of 19,000 x 10,700 km (11,800 x 6,700 miles or 27 x 15 arcseconds).

The diameter of the Earth is about 18,000 km, so the first “video” covers a square area that’s about two Earth diameters on each side. The Sun, in contrast, has a diameter of about 1,400,000 km—about 38 times larger than one side of this video.

History’s most amazing photo?

January 22, 2020 • 10:00 am

I almost never visit the My Modern Met site, but it must be good, as I often get suggestions from readers about articles there. I think I found this one on my own, but probably through Facebook. It’s the story of how an enterprising young photographer, Jon Carmichael, took a spectacular photo of a solar eclipse. Click on the screenshot to see the story.

The date was August 21, 2017, and you may remember that there was a total eclipse that day visible in much of the U.S. (I saw part of it, though it was overcast in Chicago). Carmichael decided to try to photograph the eclipse from in the air—on a commercial flight.

He chose a Southwest flight from Portland, Oregon to St. Louis, Missouri, which would put him in the path of the eclipse when he was in the air. But he neglected to buy the early boarding option, which was only $15, so he wasn’t sure that, given Southwest’s seating policy, he’d get a window seat on the proper side of the plane to take his picture. The site above gives the rest of the story, which features Southwest’s trademark hospitality:

When he explained his mission to the Southwest flight crew, not only did they ensure he’d get a great seat, but the captain actually went outside the plane to clean the window for a crystal clear shot. During the flight itself, the pilots circled a few times to provide all passengers with a spectacular view.

When it came time for the moment of totality, Carmichael was ready. He shot over 1,200 photos in two minutes and managed to perfectly capture the total eclipse over Snake River. It’s an image that Inc.calls “history’s most amazing photo.” A 10-foot laser-crystal c-print of 108 now hangs in Twitter’s New York offices.

The photo below, the one under discussion, is apparently a mosaic of his images that took a year to create. You can buy a print on Carmichael’s website. It truly is a stunning photo, though it’s not really one picture but a montage.

Here’s a video of the episode made by Southwest Airlines, which even shows the pilot cleaning the window.

Carmichael and the pilots:

Readers’ wildlife photos

September 7, 2019 • 7:45 am

We have contributions from two readers today. First, Tim Anderson of Oz sent some nice astronomy photos; his notes are indented:

This is an image of the Helix Planetary Nebula taken on 5 September. Planetary nebulae have nothing to do with planets, early European astronomers thought they looked like planets and the name stuck, Rather, they are the gaseous remnants of stars that were too small to explode in a supernova. The shells of gas were blown off the star’s surface as the star contracted under its own gravitational pressure. Interestingly, planetary nebula last only a cosmological eyeblink – as little as 10,000 years before they fade to invisibility.

This image is of the Carina Nebula, one of the most active star-forming regions in the Milky Way galaxy. Sixty 60-second images taken with a Skywatcher Esprit 100mm refractor, ASI071MCPro, UV/IR cut filter, and an EQ8 mount.

This image shows a set of emission and reflection nebulae embedded in the Sagittarius Constellation (the objects are formally known as IC 6559, 4685, 1274 and 1275). The dark “river” running between the two bright stars to the left is an absorption nebula known as B303. Imaged with a Skywatcher 254mm F4 Newtonian telescope, an ASI071MC Pro camera on an EQ8 mount. The image comprises ninety 90-second frames stacked and post-processed to taste. 

And an orthopteran from Amy Edmonds:

You probably can’t count this as a nature photo, but I thought I’d share this perfect little visitor to my deck today.  His coloring is so perfect I almost touched him to try to move him (it), thinking it was a budding flower that was stuck between the vine and the trellis.  I watched him for awhile.  When he got to the top of the trellis he seemed to be thinking how to get back down when there was no more trellis to climb on.

Reader’s wildlife photo

July 8, 2019 • 7:45 am

Remember that on this website, astronomy and nature photos count as “wildlife”. This is a photo from reader Tim Anderson in Australia, whose words are indented:

This is a picture of the Trifid Nebula or NGC6514. Its name has nothing to do with the John Wyndham novel “Day of the Triffids”, but instead derives from the Latin, meaning “divided into three lobes”. It was first described by Charles Messier on 5 June 1764 and is catalogued as Messier 20.
The red area is an emission nebula rich in hydrogen gas, which glows ruby red and has many star-forming regions embedded in it. The blue area is a “reflection nebula”, which reflects the energy from the red region. Additionally, the dark lanes crossing the emission nebula form an “absorption nebula” of thick gas and dust, which absorbs all light from the nebula behind. It is unusual to see all three types of nebulae in such close proximity.
The open star cluster towrds the bottom left is NGC6531, also catalogued by Messier as M21.
The image was formed from fifty 180-second colour exposures using a 100mm refracting telescope.
Click to enlarge: