Category Archives: Galileo’s Pendulum

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White dwarfs are the remnants of the cores of stars like our Sun. They have the mass of a star packed into the volume of Earth, but when they die, their light can be detected across the observable Universe. Researchers using the Hubble Space Telescope identified the farthest white dwarf supernova yet seen, one which exploded more than 10 billion years ago.

Only 8 white dwarf supernovas have been identified farther than 9 billion light-years away. (Some core-collapse supernovas, which are the explosions of very massive stars, have been seen farther than Supernova Wilson.) Since all such explosions happen in a similar way, cosmologists use them to measure the expansion rate of the Universe. [Read more...]

I gotta say, though: this supernova was nicknamed “Woodrow Wilson”, which kind of bugs me. Wilson was a war president, which means we Americans tend to give him a pass on a lot of things, but both his foreign and domestic policies reeked of racism. He worked against racial equality at home and abroad, stamping on egalitarian movements in the League of Nations and segregating the Federal Government. (The previous Republican administrations, for all their faults, had been making efforts to give African-Americans a voice after the Civil War.) Anyway, that’s mostly beside the point. If you want to read about a supernova named for someone whose work I do admire (prickly though he was), see my post about Supernova Mingus.

Death of a white dwarf, 10 billion years later

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OK, I might be feeling a little cranky about this, but my article for Ars Technica is a little more measured. I’ll have a longer analysis for Galileo’s Pendulum tomorrow, for those who want it. The short version: the Alpha Magnetic Spectrometer (AMS-02) is a particle detector installed on the International Space Station. For several months, the lead investigator has been hinting that AMS-02 detected the signature of dark matter annihilation: collisions between dark matter particles producing an excess of positrons. However, the actual research paper was rather short on dark matter, however interesting the AMS-02 results really were.

The Alpha Magnetic Spectrometer (AMS-02) is a particle detector based on the International Space Station, designed for looking at a variety of particles from many sources, among them dark matter collisions. Recently, the AMS-02 research team announced the results of its first 18 months of data collection. These results are frustratingly ambiguous: while AMS-02 found an excess of certain type of particle expected from some models of dark matter annihilation, this excess didn’t bear the hallmarks predicted for a dark matter signature. So, something interesting is going on in the AMS-02 data, but the chances of dark matter being the cause seem a bit low. [Read more...]

Update: I published my rant over at Galileo’s Pendulum, explaining exactly why I’m grumpish about the way these results were announced and characterized in much of the media.

Much ado about nothing in today’s dark matter non-announcement

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The cosmic pie, via Planck. [Credit: ESA/Planck Collaboration]

The cosmic pie, via Planck. [Credit: ESA/Planck Collaboration]

For cosmology-lovers like me, yesterday was a full, busy day. The Planck telescope released its first full set of data, refining the estimates of the age of the Universe and its contents. I wrote two big pieces, one for Ars Technica and one for Galileo’s Pendulum.

  • First Planck results: the Universe is still weird and interesting [Ars Technica]. “By comparing theoretical models to the real CMB, cosmologists determined that dark energy—the mysterious substance driving cosmic acceleration—comprises 68.3 percent of the energy content of the Universe, down slightly from earlier estimates of 72.8 percent. Similarly, dark matter’s contribution was boosted from 22.7 percent to 26.8 percent, while ordinary matter’s share went from 4.5 percent to 4.9 percent.”
  • Planck results: our weird and wonderful Universe [Galileo's Pendulum].  “The big news today is that our Universe is a little older than we thought, has a little more matter in it, and is every bit as strange as we’ve come to expect. Some numbers got shifted around a bit, but things are pretty much what we cosmology-watchers expected. It’s not a bad thing, in my opinion. After all, we still don’t know what dark matter is, we still don’t know what dark energy is, and we still don’t understand inflation completely. Adding weirdness to weirdness is probably more than our poor brains could take right now.”

Charlie Petit at the Knight Journalism Tracker also has a great round-up of articles on Planck, for those who want a more mainstream approach than my “techy” one (to use Petit’s term).

Planck: news from the infant Universe

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"A" is for axion (Alphabet of Cosmology)

Reblogged from Galileo's Pendulum:

Click to visit the original post

Wot's all this, now?

Today I begin a new feature, which I will try to update once a week: the Alphabet of Cosmology. In these entries, I'll highlight a  concept, experiment, or observation in cosmology—the study of the history, contents, and evolution of the Universe—that may not be as familiar to non-specialists.

(I stole borrowed this idea from Brian Switek…

Read more… 1,123 more words

I just started a new series: the Alphabet of Cosmology! Go check out the first entry: A is for Axion.
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Somewhere, something incredible is waiting to be known. – Carl Sagan, born November 9, 1934

Carl Sagan in 1980. [Credit: NASA/JPL]

Like many science writers, I count Carl Sagan as one of my inspirations and influences. However, I think there’s a tendency to mourn his absence (he died relatively young) in the wrong way: by negatively contrasting current science communicators with him, as though there needs to be One True Sagan, with everyone else failing to meet his standard. That’s a fallacy of thought and a failure of imagination.

I think there is a tendency to idolize Sagan, which is (as usual with idolization) unfair both to him and to others who would try to communicate science. In this era of media fragmentation, it may not even be possible for a single figure to be as popular or recognizable, but I don’t think that’s necessarily a bad thing. Instead of a single Sagan, why not many? [Read more...]

Happy birthday, Carl Sagan!

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The business end of a Rocketdyne F-1 rocket engine, used in the first stage of the Saturn V rockets. Five of these engines were used to launch the Apollo missions into space. Note the picnic tables at left for scale comparison.

For the next two weeks, I am on the move, traveling to various observatories in the American south and southwest, as part of the research for my book-in-progress Back Roads, Dark Skies: A Cosmological Journey. This morning, I will be visiting the Laser Interferometer Gravitational-wave Observatory (LIGO) near Livingston, Louisiana, before heading west to other observatories in Texas, New Mexico, and Arizona. My full itinerary is over at Galileo’s Pendulum:

Being a travel book, though, I am also seeking a new way to see through travel and exploration. Cosmology is a very familiar field to me, but often the person closest to a subject is the worst to try to explain it to a lay audience. By going to particle physics labs and astronomical observatories, I am learning to see my own discipline in a new way, in hopes that it will help me bring it to my readers. As you can tell, this book is different from most cosmology books (A Brief History of Time is perhaps the best example), where the focus is on highly speculative ideas and Big Theories. While theory will always inform the research I discuss—and, being a theorist myself, I can’t help but discuss theory—the primary emphasis of Back Roads, Dark Skies is on experiment and observation. Without these things, theory is nothing but the ramblings of creative people, unconnected to reality. [Read more...]

While the scientific part of the agenda begins today, I haven’t been idly driving without keeping an eye out for interesting things. To wit: yesterday, I saw a wild alligator and one of the engines from the Saturn V rockets, which were used to launch the Apollo missions and the Skylab space station.

The Bowler Hat is on the move

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Every exoplanet discovery seems to bring us closer to understanding the variety of planetary systems out there in our galaxy. The latest find is particularly exciting: an Earth-mass planet orbiting around Alpha Centauri B, one of three stars in the closest system to the Solar System. The planet isn’t very Earthlike in most respects, but it’s still an incredibly exciting discovery.

However, the discovery is still exciting for a number of reasons. First is the proximity of the star system to us: Alpha Centauri is 4.4 light years away, a tiny distance in cosmic terms. The stars Alpha Centauri A and B are some of the brightest in the sky in the Southern Hemisphere. (Sorry, fellow Northern Hemisphere-dwellers; we can’t see them from here.) We don’t have starship technology to travel there, but we could conceivably send a robotic probe that could arrive within my lifetime, and 4.4 years isn’t a terribly long time for data to travel back to Earth. No one has such a probe in the works yet, but the mere fact of discovery of a planet might encourage investment in that direction. [Read more...]

Alpha Centauri harbors an Earth-mass planet

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Ada Lovelace, 1815-1852 [Credit: Wikipedia]

For Ada Lovelace Day, I compiled a list of many of the best science writers I know:

Last year, I celebrated Emmy Noether, perhaps the greatest mathematician of the 20th century. This year (largely because I’m swamped with other work), I’m stealing a great idea from Ed Yong, and celebrating living writers who are my friends, colleagues, and influences. This list is in no particular order, isn’t anywhere close to complete, and has some overlap with Ed’s list. My main criteria are that these are writers I read regularly, so their interests mix with mine to some degree. (Writers marked with an asterisk* are people I have met in Real Life, whatever that signifies.) Leave your own favorites and influences in the comments! [Read more....]

Happy Ada Lovelace Day!

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Yesterday, Austrian skydiver Felix Baumgartner (best known for jumping off skyscrapers) successfully completed a 39 kilometer dive from a balloon. Many media outlets described his jump as beginning “at the edge of space”, but the story is a little more complex than that.

One thing bothered me, though, about a lot of the coverage: many people said Baumgartner was jumping “from space” or “from the edge of space”. Don’t get me wrong—39 km is a long way up, about 4 times the altitude of commercial airliners, so I’m not denigrating this accomplishment at all. Atmospheric pressure is about 2% of its value at Earth’s surface at 39 km, and the temperatures are pretty cold, so Baumgartner had to wear a pressurized suit and carry an air supply. (If memory serves, the temperature was -7° C or 19° F when the dive began.) However, it’s not what is conventionally considered “space”: it’s within the region of Earth’s atmosphere known as the stratosphere (which also explains the project’s official name, “Stratos Jump”). So, if Baumgartner didn’t jump from space, where is the boundary of space? [Read more....]

Jumping from the “edge of space”…whatever that means

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The Nobel Prizes recognize good scientific achievements, but in many ways the attention they get is disproportionate to their value, and presents a false view of how science really works.

Part of the problem instead is that the Nobel Prizes perpetuate the idea of a handful of Great Men (only two women have won the Nobel Prize in physics total since their establishment), toiling alone in their laboratories. The published papers cited in the Nobel literature belie that: many coauthors contribute to the majority of research now, and a single seminal (there’s that masculine imagery again) paper generally isn’t what establishes a research program as worthy of accolades. As a result, every Nobel Prize discussion seems to involve complaints about why some scientists were included, and some ignored. [Read more....]

A Nobel Prize curmudgeon speaks out