Astronomy Archives

February 16, 2010December 24, 2015 by Jean Tate

Youngsters Caught Gorging – on Gas

Typical massive galaxy at z=1.1 (left: V, I (Hubble); right: CO 3-2 mm emission (IRAM); copyright MPE/IRAM)

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Galaxies long, long ago were very fecund; they gave birth to stars at a rate at least ten times what we see today.

Why? Was there more stuff around then, to make stars? Or were galaxies back then more efficient at star-making? Or something else??

Dr. Linda Tacconi, from Germany’s Max-Planck-Institut für extraterrestrische Physik, led an international team of astronomers to find out why … and the answer seems to be that young galaxies were stuffed to the gills with gas.

“We have been able, for the first time, to detect and image the cold molecular gas in normal star forming galaxies, which are representative of the typical massive galaxy populations shortly after the Big Bang,” said Dr Tacconi.

The challenging observations yield the first glimpse how galaxies, or more precisely the cold gas in these galaxies, looked a mere 3 to 5 billion years after the Big Bang (equivalent to a cosmological redshift z~2 to z~1). At this age, galaxies seem to have formed stars more or less continuously with at least ten times the rate seen in similar mass systems in the local Universe.

It is now reasonably well-established that galaxies formed from proto-galaxies, which themselves formed in local over-densities, dominated by cold dark matter – dark matter halos – where the newly neutral hydrogen and helium collected and cooled. Through collisions and mergers, and some on-going gas accretion, the proto-galaxies formed young galaxies, a few billion years after the Big Bang – in short, hierarchical formation.

The Plateau de Bure millimetre interferometer in the southern French Alps. Copyright: IRAM

Detailed observations of the cold gas and its distribution and dynamics hold a key role in disentangling the complex mechanisms responsible for turning the first proto-galaxies into modern galaxies, such as the Milky-Way. A major study of distant, luminous star forming galaxies at the Plateau de Bure millimeter interferometer has now resulted in a breakthrough by having a direct look at the star formation “food”. The study took advantage of major recent advances in the sensitivity of the radiometers at the observatory to make the first systematic survey of cold gas properties (traced by a rotational line of the carbon monoxide molecule) of normal massive galaxies when the Universe was 40% (z=1.2) and 24% (z=2.3) of its current age. Previous observations were largely restricted to rare, very luminous objects, including galaxy mergers and quasars. The new study instead traces massive star forming galaxies representative of the ‘normal’, average galaxy population in this mass and redshift range.

“When we started the programme about a year ago”, says Dr. Tacconi, “we could not be sure that we would even detect anything. But the observations were successful beyond our most optimistic hopes. We have been able to demonstrate that massive normal galaxies at z~1.2 and z~2.3 had five to ten times more gas than what we see in the local Universe. Given that these galaxies were forming gas at a high rate over long periods of time, this means that gas must have been continuously replenished by accretion from the dark matter halos, in excellent agreement with recent theoretical work.”

Another important result of these observations is the first spatially resolved images of the cold gas distribution and motions in several of the galaxies. “This survey has opened the door for an entirely new avenue of studying the evolution of galaxies,” says Pierre Cox, the director of IRAM. “This is really exciting and there is much more to come.”

“These fascinating findings provide us with important clues and constraints for next-generation theoretical models that we will use to study the early phases of galaxy development in more detail,” says Andreas Burkert, specialist for star formation and the evolution of galaxies at Germany’s Excellence Cluster Universe. “Eventually these results will help to understand the origin and the development of our Milky Way.”

About the EGS 1305123 image: Spatially resolved optical and millimeter images of a typical massive galaxy at redshift z=1.1 (5.5 billion years after the Big Bang). The left image was taken with the Hubble Space Telescope in the V- and I-optical bands, as part of the AEGIS survey of distant galaxies. The right image is an overlay of the CO 3-2 emission observed with the PdBI (red/yellow colors) superposed on the I-image (grey). For the first time these observations clearly show that the molecular line emission and the optical light from massive stars trace a massive, rotating disk of diameter ~60,000 light years. This disk is similar in size and structure as seen in z~0 disk galaxies, such as the Milky Way. However, the mass of cold gas is in this disk is about an order of magnitude larger than in typical z~0 disk galaxies. This explains why high-z galaxies can form continuously at about ten times the rate of typical z~0 galaxies.

Sources: Max Planck Institute for Extraterrestrial Physics, Tacconi et al. (2010), Nature 463, 781 (preprint: arXiv:1002.2149)

February 15, 2010December 24, 2015 by Jean Tate

Proton Parts

The proton has three parts, two up quarks and one down quark … and the gluons which these three quarks exchange, which is how the strong (nuclear) force works to keep them from getting out.

The proton’s world is a totally quantum one, and so it is described entirely by just a handful of numbers, characterizing its spin (a technical term, not to be confused with the everyday English word; the proton’s spin is 1/2), electric charge (+1 e, or 1.602176487(40)×10^-19 C), isospin (also 1/2), and parity (+1). These properties are derived directly from those of the proton parts, the three quarks; for example, the up quark has an electric charge of +2/3 e, and the down -1/3 e, which sum to +1 e. Another example, color charge: the proton has a color charge of zero, but each of its constituent three quarks has a non-zero color charge – one is ‘blue’, one ‘red’, and one ‘green’ – which ‘sum’ to zero (of course, color charge has nothing whatsoever to do with the colors you and I see with our eyes!).

Murray Gell-Mann and George Zweig independently came up with the idea that the proton’s parts are quarks, in 1964 (though it wasn’t until several years later that good evidence for the existence of such parts was obtained). Gell-Mann was later awarded the Nobel Prize of Physics for this, and other work on fundamental particles (Zweig has yet to receive a Nobel).

The quantum theory which describes the strong interaction (or strong nuclear force) is quantum chromodynamics, QCD for short (named in part after the ‘colors’ of quarks), and this explains why the proton has the mass it does. You see, the up quark’s mass is about 2.4 MeV (mega-electron volts; particle physicists measure mass in MeV/c²), and the down’s about 4.8 MeV. Gluons, like photons, are massless, so the proton should have a mass of about 9.6 MeV (= 2 x 2.4 + 4.8), right? But it is, in fact, 938 MeV! QCD accounts for this enormous difference by the energy of the QCD vacuum inside the proton; basically, the self-energy of ceaseless interactions of quarks and gluons.

Further reading: The Physics of RHIC (Brookhaven National Lab), How are the protons and neutrons held together in a nucleus?, and Are protons and neutrons fundamental? (the Particle Adventure) are three good places to go!

Some of the Universe Today articles relevant to proton parts are: Final Detector in Place at the Large Hadron Collider, Hidden Stores of Deuterium Discovered in the Milky Way, and New Study Finds Fundamental Force Hasn’t Changed Over Time.

Two Astronomy Cast episodes you won’t want to miss, on proton parts: The Strong and Weak Nuclear Forces, and Inside the Atom.

Sources:
Chem4Kids
Wikipedia

February 15, 2010May 4, 2017 by Jean Tate

Gravity Equation

There is not one, not two, not even three gravity equations, but many!

The one most people know describes Newton’s universal law of gravitation:

F = Gm₁m₂/r²,
where F is the force due to gravity, between two masses (m₁ and m₂), which are a distance r apart; G is the gravitational constant.

From this is it straightforward to derive another, common, gravity equation, that which gives the acceleration due to gravity, g, here on the surface of the Earth:

g = GM/r²,
Where M is the mass of the Earth, r the radius of the Earth (or distance between the center of the Earth and you, standing on its surface), and G is the gravitational constant.

With its publication in the early years of the last century, Einstein’s theory of general relativity (GR) became a much more accurate theory of gravity (the theory has been tested extensively, and has passed all tests, with flying colors, to date). In GR, the gravity equation usually refers to Einstein’s field equations (EFE), which are not at all straight-forward to write, let alone explain (so I’m going to write them … but not explain them!):

G_?? = 8?G/c⁴ T_??

G (without the subscripts) is the gravitational constant, and c is the speed of light.

Finally, here’s a acceleration of gravity equation you’ve probably never heard of before:

a = ?(GMa₀/r),

where a is the acceleration a star feels, due to gravity under MOND (MOdified Newtonian Dynamics), an alternative theory of gravity, M is the mass of a galaxy, r the distance between the star in the outskirts of that galaxy and its center, G the gravitational constant, and a₀ a new constant.

Some websites which contain more on gravity equations, for your interest and enjoyment: Newton’s Theory of “Universal Gravitation” (NASA), Einstein’s equation of gravity (University of Wisconsin Madison – heavy), and Gravity Formula (University of Nebraska-Lincoln).

Universe Today, as you would expect, has several stories relevant to gravity equations; here are a few: See the Universe with Gravity Eyes, A Case of MOND Over Dark Matter, and Flyby Anomalies Explained?. Here’s an article about 0 gravity.

Gravity, an Astronomy Cast episode, has more on gravity equations, as do several Astronomy Cast Question Shows, such as September 26th, 2008, and March 31st, 2009.

Sources:
University of Nebraska-Lincoln
NASA
UT-Knoxville

February 15, 2010December 24, 2015 by Jean Tate

Galaxy Names

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Galaxy names come in a bewildering range of forms; from descriptive (e.g. Whirlpool Galaxy, Black Eye Galaxy, The Eyes), to ones that seem to relate to a constellation (e.g. Andromeda Galaxy, Hydra A, Leo I), to ones named after a person (e.g. Stephan’s Quintet, Malin I, Mayall’s Object), to letter+number combinations (e.g. the Messier catalog galaxies such as M33 and M87), to letters+number combinations (e.g. NGC 3115, DDO 185), to impossible-to-remember stings-with-dashes-dots-and-pluses like MCG-06-07-001, 4C37.11, and SDSS J002240.91+143110.4!

And sometimes a galaxy has LOTS of different names, such as M87, Virgo A, NGC 4486, Arp 152, 3C274, IRAS 12282+1240, WMAP J123051+1223 (there’s, like, about another 20!).

However, of the estimated 100 billion galaxies we could observe, with current astronomical facilities, only a few million have names, and most of those are unique (i.e. only one name per galaxy). Of course, almost all the single-name galaxies are little more than faint smudges in an optical or infrared image … and that gives a clue to where the names come from!

Most galaxy names come from the catalog, or catalogs, in which they appear. The catalogs have many sources, but most recent ones have been put together as a key output of a dedicated survey or mission, and the galaxy name reflects that. So, for example, SDSS stands for Sloan Digital Sky Survey (one of the most amazing optical/NIR galaxy surveys of all time), IRAS for InfraRed Astronomy Satellite, DDO for David Dunlap Observatory (where a catalogue of dwarf galaxies was put together), and 4C for 4th Cambridge survey (a radio survey). Some of the older catalogs, or lists, were put together from previously known galaxies, or objects (the Messier list is perhaps the most famous example).

More to explore, on galaxy names. The online dedicated, searchable database NED (NASA/IPAC Extragalactic Database) is astronomers’ essential resource; SEDS’ (Students for the Exploration and Development of Space, hosted by the University of Arizona LPL) Messier galaxy section is amateurs’ favorite; and Galaxy names are identified by a group of letters and numbers. What do they stand for? (Hubblesite).

Universe Today articles on galaxy names? Sure! Here is a small sample: This Where in the Universe Challenge, Astrophoto: NGC 4631 by Bernd Wallner, and Have a Cigar! New Observations of Messier 82.

Astronomy Cast’s Milky Way episode has more on galaxy names; well worth a listen!

Sources: Hubblesite, SDSS, IRAS, DDO, NASA/IPAC

February 15, 2010December 24, 2015 by Tammy Plotner

Stereo “Soul” – A Visualization by Jukka Metsavanio

Seeing double? Darn right you are. It’s been awhile since I’ve featured any of Jukka Metsavanio’s brilliant visualizations… and things have gotten even more incredible since. Step inside and prepare to get blown away by “Stereo Soul”…

As always, whenever we present a dimensional visualization it is done in two fashions. The first is called “Parallel Vision” and it is much like a magic eye puzzle. When you open the full size image and your eyes are the correct distance from the screen, the images will seem to merge and create a 3D effect. However, for some folks, this doesn’t work well – so Jukka has also created the “Cross Version”, where you simply cross your eyes and the images will merge, creating a central image which appears 3D. For some folks, this won’t work either… But I hope it does for you!

Now, let’s learn a little bit about IC1848, the “Soul Nebula”…

Located about 6,500 light-years away in the constellation Cassiopeia, this complex of emission nebulae contain a radio source called W5. The stellar winds and intense radiation from the region’s most massive stars have carved out a black “holes” in the nebula. However, unlike the black holes that signal the death of a star, these forming cavities push the gases together and trigger new star formation. Younger stars line the rims of the cavities, while older ones form clumps and knots.

Let’s give them a fly-by…

Parallel Vision

Cross Vision

Can’t see “Stereo Soul”? Then have a look at this…

And be sure to thank J.P. Metsavanio for sharing his incredible visions with us!

February 15, 2010December 24, 2015 by Fraser Cain

Galaxy Pics

Hubble Observes Infant Stars in Nearby Galaxy

Here are some beautiful galaxy pics. You can even use these as desktop background wallpapers if you like. Just click on an image to see a larger version and then right-click and choose “Set as Desktop Background”.

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This is a picture of a cluster of stars in the nearby satellite galaxy, the Small Magellanic Cloud. These bright young stars are blasting out a bubble of gas and dust with their powerful stellar winds.

This is a Hubble Space Telescope image of the nearby galaxy Centaurus A. The supermassive black hole at the heart of Centaurus A is currently feeding on a smaller galaxy that recently collided. Cosmic collisions like this were common in the early Universe, but they happen less frequently now with more space in between galaxies.

This is a photograph of the galaxy NGC 4526, captured by the Hubble Space Telescope. You can also see a bright star below the galaxy; it’s not a star at all, but a supernova that was imaged as part of this photograph.

This is an image of the galaxy cluster MACS J0717 captured by NASA’s Chandra X-Ray Observatory. The image from Chandra lets astronomers see where large clouds of hot gas are colliding together, heating up to millions of degrees.

This is an artist’s impression of what a galaxy might have looked like in the early Universe, just a billion years after the Big Bang. Stars formed out of the primordial hydrogen left over from the Big Bang, grew large and then detonated as supernovae, seeding the Universe with heavier elements.

We’ve written many articles about galaxies for Universe Today. Here is a story about how many galaxies there are in the Universe, and here is an article about how many galaxies we have discovered.

If you’d like more info on galaxies, check out Hubblesite’s News Releases on Galaxies, and here’s NASA’s Science Page on Galaxies.

We’ve also recorded an episode of Astronomy Cast about galaxies. Listen here, Episode 97: Galaxies.

February 15, 2010December 24, 2015 by Jean Tate

Supermassive Black Holes Spinning Backwards Create Death Ray Jets?

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Why do some of the supermassive black holes in active galactic nuclei create back-to-back jets that can vaporize entire solar systems, while others have no jets at all?

Dan Evans, a postdoctoral researcher at MIT Kavli Institute for Astrophysics and Space Research (MKI) thinks he knows why; it’s because the jet-producing supermassive black holes are spinning backwards, relative to their accretion disks.

Radio image of a typical DRAGN, showing the main features (Image credit:C. L. Carilli)

For two years, Evans has been comparing several dozen galaxies whose black holes host powerful jets (these galaxies are known as radio-loud active galactic nuclei, or AGN, and are often DRAGNs – double radio source associated with galactic nucleus) to those galaxies with supermassive black holes that do not eject jets. All black holes – those with and without jets – feature accretion disks, the clumps of dust and gas rotating just outside the event horizon. By examining the light reflected in the accretion disk of an AGN black hole, he concluded that jets may form right outside black holes that have a retrograde spin – or which spin in the opposite direction from their accretion disk. Although Evans and a colleague recently hypothesized that the gravitational effects of black hole spin may have something to do with why some have jets, Evans now has observational results to support the theory in a paper published in the Feb. 10 issue of the Astrophysical Journal.

Although Evans has suspected for nearly five years that retrograde black holes with jets are missing the innermost portion of their accretion disk, it wasn’t until last year that computational advances meant that he could analyze data collected between late 2007 and early 2008 by the Suzaku observatory, a Japanese satellite launched in 2005 with collaboration from NASA, to provide an example to support the theory. With these data, Evans and colleagues from the Harvard-Smithsonian Center for Astrophysics, Yale University, Keele University and the University of Hertfordshire in the United Kingdom analyzed the spectra of the active galactic nucleus with a pair of jets located about 800 million light years away in an AGN named 3C 33.

1477 MHz image of 3C 33 (Credit: Leahy & Perley (1991))

“It’s the first convincing galaxy of this type seen at this angle where the result is pretty robust,” said Patrick Ogle, an assistant research scientist at the California Institute of Technology, who studies AGN. Ogle believes Evans’s theory regarding retrograde spin is among the best explanations he has heard for why some AGN contain a supermassive black hole with a jet and others don’t.

Astrophysicists can see the signatures of x-ray emission from the inner regions of the accretion disk, which is located close to the edge of a black hole, as a result of a super hot atmospheric ring called a corona that lies above the disk and emits light (electromagnetic radiation) that an observatory like Suzaku can detect. In addition to this direct light, a fraction of light passes down from the corona onto the black hole’s accretion disk and is reflected from the disk’s surface, resulting in a spectral signature pattern called the Compton reflection hump, also detected by Suzaku.

But Evans’ team never found a Compton reflection hump in the x-ray emission given off by 3C 33, a finding the researchers believe provides crucial evidence that the accretion disk for a black hole with a jet is truncated, meaning it doesn’t extend as close to the center of the black hole with a jet as it does for a black hole that does not have a jet. The absence of this innermost portion of the disk means that nothing can reflect the light from the corona, which explains why observers only see a direct spectrum of x-ray light.

The researchers believe the absence may result from retrograde spin, which pushes out the orbit of the innermost portion of accretion material as a result of general relativity, or the gravitational pull between masses. This absence creates a gap between the disk and the center of the black hole that leads to the piling of magnetic fields that provide the force to fuel a jet.

While Ogle believes that the retrograde spin theory is a good explanation for Evans’ observations, he said it is far from being confirmed, and that it will take more examples with consistent results to convince the astrophysical community.

The field of research will expand considerably in August 2011 with the planned launch of NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) satellite, which is 10 to 50 times more sensitive to spectra and the Compton reflection hump than current technology. NuSTAR will help researchers conduct a “giant census” of supermassive black holes that “will absolutely revolutionize the way we look at X-ray spectra of AGN,” Evans explained. He plans to spend another two years comparing black holes with and without jets, hoping to learn more about the properties of AGN. His goal over the next decade is to determine how the spin of a supermassive black hole evolves over time.

Sources: MITnews, Evans’ Astrophysical Journal paper (preprint is arXiv:1001.0588)

February 15, 2010December 24, 2015 by Nancy Atkinson

Sources of Cosmic Rays Found? Fermi Telescope Closes In

A multiwavelength look at Cas A. Credit: NASA/DOE/Fermi LAT Collaboration

The origin of cosmic rays has been a mystery since their discovery nearly a century ago. But new images from the Fermi Gamma-ray Space Telescope may bring astronomers a step closer to understanding the source of the Universe’s most energetic particles. The images show where supernova remnants emit radiation a billion times more energetic than visible light. “Fermi now allows us to compare emission from remnants of different ages and in different environments,” said Stefan Funk, an astrophysicist at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC).

Cosmic rays are made up of electrons, positrons and atomic nuclei and they constantly bombard the Earth. In their near-speed-of-light journey across the galaxy, the particles are deflected by magnetic fields, which scramble their paths and mask their origins. When cosmic rays collide with interstellar gas, they produce gamma rays. While instruments can infer the presence of cosmic rays by looking for the glow of gamma ray emissions, so far, no specific sources have been located. .

“Understanding the sources of cosmic rays is one of Fermi’s key goals,” said said Funk, who presented the new images and findings at the American Physical Society meeting in Washington, D.C. on Monday.

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Fermi’s Large Area Telescope (LAT) mapped billion-electron-volt (GeV) gamma rays from three middle-aged supernova remnants — known as W51C, W44, and IC 443 — that were never before resolved at these energies. (The energy of visible light is between 2 and 3 electron volts.) Each remnant is the expanding debris of a massive star that blew up between 4,000 and 30,000 years ago.

In addition, Fermi’s LAT also spied GeV gamma rays from Cassiopeia A (Cas A), a supernova remnant only 330 years old. Ground-based observatories, which detect gamma rays thousands of times more
energetic than the LAT was designed to see, have previously detected Cas A.

“Older remnants are extremely bright in GeV gamma rays, but relatively faint at higher energies. Younger remnants show a different behavior,” explained Yasunobu Uchiyama, a Panofsky Fellow at SLAC. “Perhaps the highest-energy cosmic rays have left older remnants, and Fermi sees emission from trapped particles at lower energies.”

Fermi mapped GeV-gamma-ray emission regions (magenta) in the W44 supernova remnant. The features clearly align with filaments detectable in other wavelengths. This composite merges X-ray data (blue) from the Germany/U.S./UK ROSAT mission, infrared (red) from NASA’s Spitzer Space Telescope, and radio (orange) from the Very Large Array near Socorro, N.M. Credit: NASA/DOE/Fermi LAT Collaboration, NASA/ROSAT, NASA/JPL-Caltech, and NRAO/AUI

In 1949, physicist Enrico Fermi — for whom the Fermi telescope was named –suggested that the highest-energy cosmic rays were accelerated in the magnetic fields of gas clouds. In the decades that followed,
astronomers showed that supernova remnants are the galaxy’s best candidate sites for this process.

Young supernova remnants seem to possess both stronger magnetic fields and the highest-energy cosmic rays. Stronger fields can keep the highest-energy particles in the remnant’s shock wave long enough to speed them to the energies observed.

The Fermi observations show GeV gamma rays coming from places where the remnants are known to be interacting with cold, dense gas clouds.

“We think that protons accelerated in the remnant are colliding with gas atoms, causing the gamma-ray emission,” Funk said. An alternative explanation is that fast-moving electrons emit gamma rays as they fly past the nuclei of gas atoms. “For now, we can’t distinguish between these possibilities, but we expect that further observations with Fermi will help us to do so,” he added.

Either way, these observations validate the notion that supernova remnants act as enormous accelerators for cosmic particles.

“How fitting it is that Fermi seems to be confirming the bold idea advanced over 60 years ago by the scientist after whom it was named,” noted Roger Blandford, director of KIPAC.

Source: Fermi/Sonoma State University

February 14, 2010December 24, 2015 by Jean Tate

Gemini’s New Filters Reveal the Beauty of Star Birth

Sharpless 2-106 (Gemini Observatory/AURA, right; left: copyright Subaru Telescope, National Astronomical Observatory of Japan; All rights reserved)

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About 2,000 light-years away, in the constellation of Cygnus (the Swan), lies Sharpless 2-106 (after Stewart Sharpless who put the catalog together in 1959), the birth-place of a star cluster-to-be.

Two recent image releases – by Subaru and Gemini – showcase their new filter sets and image capabilities; they also reveal the stunning beauty of the million-year-long process of the birth of a star.

Sharpless 2-106 (Gemini Observatory/AURA)

The filter set is part of the Gemini Multi-Object Spectrograph (GMOS) toolkit, and includes ones centered on the nebular lines of doubly ionized oxygen ([OIII] 499 nm), singly ionized sulfur ([SII] 672 nm), singly ionized helium (HeII 468nm), and hydrogen alpha (Hα 656 nm). The filters are all narrowband, and are also used to study planetary nebulae and excited gas in other galaxies.

The hourglass-shaped (bipolar) nebula in the new Gemini image is a stellar nursery made up of glowing gas, plasma, and light-scattering dust. The material shrouds a natal high-mass star thought to be mostly responsible for the hourglass shape of the nebula due to high-speed winds (more than 200 kilometers/second) which eject material from the forming star deep within. Research also indicates that many sub-stellar objects are forming within the cloud and may someday result in a cluster of 50 to 150 stars in this region.

The nebula’s physical dimensions are about 2 light-years long by 1/2 light-year across. It is thought that its central star could be up to 15 times the mass of our Sun. The star’s formation likely began no more than 100,000 years ago and eventually its light will break free of the enveloping cloud as it begins the relatively short life of a massive star.

For this Gemini image four colors were combined as follows: Violet – HeII filter; Blue – [SII] filter; Green – [OIII] filter; and Red – Hα filter.

Sharpless 2-106 (Copyright Subaru Telescope, National Astronomical Observatory of Japan. All rights reserved)

The Subaru Telescope image was made by combining images taken through three broadband near-infrared filters, J (1.25 micron), H (1.65 micron), and K’ (2.15 micron).

Sources: Gemini Observatory, NAOJ

February 14, 2010April 26, 2016 by Nancy Atkinson

For Valentine’s Day: Hearts in Space from Sixty Symbols

Yes, we humans excel at seeing patterns and shapes everywhere around us, including out in space. Here, the folks from Sixty Symbols (featuring my friend Astropixie a.k.a Amanda Bauer) celebrate Valentine’s Day by showing several heart-shaped astronomical. Also, as explained in the video, 20 years ago today — on February 14, 1990 — the Voyager 1 spacecraft took the famous “Pale Blue Dot” image, where it turned around and took a picture of Earth. From 6 billion kilometers (4 billion miles) away Earth appeared as a “mote of dust suspended in a sunbeam” as Carl Sagan phrased it. It truly is one of the most “romantic” images ever as it can’t help but evoke strong emotions by anyone who sees it. “That’s here, that’s home, that’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives,” said Sagan.
Continue reading “For Valentine’s Day: Hearts in Space from Sixty Symbols”