Universe Today

July 4, 2013March 16, 2017 by Fraser Cain

How Many Moons Does Earth Have?

Look up into the night sky and count the moons. You can see only one moon, “the” Moon. But does the Earth have any other moons? Around the Solar System, multiple moons are the rule. Jupiter has 67 natural satellites, even Mars has two asteroid-like moons.

Could Earth have more than one?

Officially, the answer is no. The Earth has a single moon.

Today.

It’s possible Earth had more than one moon in the past, millions or even billions of years ago. Strange terrain on the far side of the Moon could be explained by a second moon crashing into it, depositing a layer of material tens of kilometers deep.

Moons could come and go over the billions of years of the Earth’s history.

For example, Mars has two Moons, but not for long. Phobos, the larger moon, is spiraling inward and expected to crash into the planet within the next 10 million years. And so, in the future, Mars will only have a single Moon, Deimos.

It’s also possible that the Earth might capture a Moon in the future. Neptune’s largest moon, Triton, orbits in the opposite direction from the rest of the moons around the planet. This suggests that Triton was actually a captured Kuiper Belt Object which strayed too close to the planet.

In fact, we did capture a 5-metre asteroid called 2006 RH120. It orbited the Earth four times during 2006/2007 before getting ejected again.

So we can assume events like this have happened in the past.

Additionally, we might have more moons, but they haven’t been discovered yet because they’re just too small. Researchers have calculated that there could be meter-sized asteroids in orbit around the Earth, remaining in orbit for hundreds of years before gravitational interactions push them out again.

And there are other objects that interact with Earth’s orbit in strange ways. Scientists don’t consider them moons, but they do stick around in our neighbourhood:

Asteroid 3753 Cruithne is in an orbital resonance with the Earth. It has a highly eccentric orbit, but takes exactly one year to orbit the Sun. From our perspective, it follows a slow, horse-shoe shaped path across the sky. Since the discovery of Cruithne in 1986, several other resonant near-Earth objects have been discovered.

There’s 2010 TK7, the Earth’s only known Trojan asteroid. It leads the Earth in the exact same orbit around the Sun, in a gravitationally stable point in space.

So, the answer… Earth only has a single Moon. Today. We might have had more moons in the past, and we might capture more in the future, but for right now… enjoy the one we’ve got.

Want to learn more? Here are some articles on Universe Today we’ve written about this topic:
What are some objects known as Earth’s other moons?
Did Earth have more than one moon in the past?
Does Earth have many tiny moons?

You might also enjoy this episode of Astronomy Cast: Where did the Moon come from?

July 4, 2013December 23, 2015 by Ken Kremer

NASA’s Independence Day Fireworks from Wallops Investigates Earth’s Global Daytime Dynamo Current

July 4 Morning Fireworks from NASA!
A NASA Black Brant V Sounding Rocket launches in support of the Daytime Dynamo Mission on July 4, 2013 from NASA Wallops Flight Facility, VA. Credit: NASA/J. Eggers[/caption]

WALLOPS ISLAND, VA – Today, July 4, NASA celebrated America’s Independence Day with a spectacular fireworks display of a dynamic duo of sounding rockets – blasting off barely 15 seconds apart this morning from the agencies NASA Wallops Island facility on the Eastern Shore of Virginia on a science experiment to study the ionosphere.

The goal of the two rocket salvo was an in depth investigation of the electrical currents in Earth’s ionosphere – called the Daytime Dynamo.

The Dynamo electrical current sweeps through the ionosphere, a layer of charged particles that extends from about 30 to 600 miles above Earth.

Disruptions in the ionosphere can scramble radio wave signals for critical communications and navigations transmissions that can impact our every day lives.

The launches suffered multiple delays over the past 2 weeks due to weather, winds, errant boats and unacceptable science conditions in the upper atmosphere.

A Black Brant V launches first in support of Daytime Dynamo. Terroer improved Orion (at right) followed 15 seconds later from NASA Wallops on July 4, 2013. Credit: NASA/P. Black

At last, the Fourth of July was the irresistible charm.

The liftoff times were 10:31:25 a.m. for the Black Brant V and 10:31:40 a.m. (EDT) for the Terrier-Improved Orion.

The experiment involved launching two suborbital rockets and also dispatching a NASA King Air airplane to collect a stream of airborne science measurements.

Daytime Dynamo is a joint project between NASA and the Japanese Space Agency, or Japan Aerospace Exploration Agency, or JAXA, said Robert Pfaff to Universe Today in an exclusive interview inside Mission Control at Wallops. Pfaff is the principle investigator for the Dynamo sounding rocket at NASA’s Goddard Space Flight Center in Greenbelt, Md.

“The dynamo changes during the day and varies with the season,” Pfaff told me.

But they only have one chance to launch. So the science team has to pick the best time to meet the science objectives.

“We would launch every month if we could and had the funding, in order to even more fully characterize the Dynamo.”

Two rocket salvo comprising a Black Brant V (left) and a Terrier-Improved Orion (right) sit ready to launch as part of the Daytime Dynamo mission in this panoramic view from NASA Wallops Flight Facility at Virginia’s Eastern Shore. Credit: Ken Kremer/kenkremer.com

The 35 foot tall single-stage Black Brant V launched first. It carried a 600 pound payload to collect the baseline data to characterize the neutral and charged ionospheric particles as it blasted skyward.

The 33 foot tall two-stage Terrier-Improved Orion took off just 15 seconds later in the wake of the exhaust of the Black Brant V.

Exhaust trails from Black Brant V and a Terrier-Improved Orion launched in support of Daytime Dynamo mission on July 4, 2013. Credit: NASA P. Black — Exhaust trails from Black Brant V and a Terrier-Improved Orion launched in support of Daytime Dynamo mission on July 4, 2013. Credit: NASA/P. Black

The Terrier-Improved Orion successfully deployed a lengthy trail of lithium gas from a pressurized canister that created a chemical tracer to track how the upper atmospheric winds vary with altitude. These winds are believed to be the drivers of the dynamo currents.

Both rockets fly for about five minutes to an altitude of some 100 miles up in the ionosphere. They both splashed down in the ocean after about 15 minutes.

NASA’s King Air aircraft was essential to the mission. I toured the airplane on the Wallops runway for an up-close look inside. It is outfitted with a bank of precisely aimed analytical instruments peering through the aircraft windows to capture the critical science data – see my photos herein.

“The King Air launches about an hour before the scheduled liftoff time,” Pfaff told me.

“It uses special cameras and filters to collect visible and infrared spectroscopic data from the lithium tracer to characterize the daytime dynamo.”

The science instruments are newly developed technology to make the daytime measurements of the lithium tracer and were jointly created by NASA, JAXA and scientists at Clemson University.

“Everything worked as planned,” Pfaff announced from Wallops Mission Control soon after the magnificent Fourth of July fireworks show this morning.

Ken Kremer

Black Brant V (left) and a Terrier-Improved Orion (right) rockets sit on launch pads as part of the Daytime Dynamo mission in this up close view from NASA Wallops Flight Facility at Virginia’s Eastern Shore. Credit: Ken Kremer/kenkremer.com — Black Brant V (left) and Terrier-Improved Orion (right) rockets sit on launch pads as part of the Daytime Dynamo mission in this up close view from NASA Wallops Flight Facility at Virginia’s Eastern Shore. Credit: Ken Kremer/kenkremer.com

Inside cabin view of NASA King Air aircraft outfitted with science instrument mounts to support a of cameras to capture visible and infrared spectroscopic measurements in support of Daytime Dynamic launches on July 4, 2013. Credit: Ken Kremer/kenkremer.com — Inside cabin view of NASA King Air aircraft outfitted with science instrument mounts to support a bank of cameras to capture visible and infrared spectroscopic measurements in support of Daytime Dynamic launches on July 4, 2013. Credit: Ken Kremer/kenkremer.com

Robert Pfaff (right), Science Principle Investigator and Ken Kremer of Universe Today (left) discuss NASA’s Daytime Dynamo mission inside NASA Wallop’s Mission Control. Credit: Ken Kremer/kenkremer.com

July 4, 2013December 23, 2015 by Elizabeth Howell

When We Look For Life Beyond Earth, Let’s Consider Dying Planets: Study

Upper Geyser Basin region in Yellowstone National Park in Wyoming. A new study supposes the Earth will look like this after the sun heats up in a few billion years' time. Credit: Jack O’Malley-James

Bacteria. They’re so resilient that they can survive just about anywhere on Earth, even in spots of extreme hot or cold. As the sun warms up in the next few billion years, it’s likely that bacteria will be the only living creatures left on the planet, according to new research.

The study not only has implications for human survival — hopefully, our descendants will have left by then — but also our search for life on other planets. By predicting the signature these bacteria leave behind on the atmosphere, we can better hone our search for new planets, the study states.

Earth’s history shows that a species, just like an individual, can expect a lifetime that only lasts for so long. Sometimes a catastrophic event will wipe out a species, like what likely happened to the dinosaurs around 65 million years ago when a huge asteroid hit the Earth. Other times, it’s a slow process that is infinitesimal in an individual’s lifetime, but will eventually lead to changes that are unfriendly for life.

Thermophilic (heat-loving) bacteria may be among the last living creatures on Earth, the study suggests. Credit: Mark Amend / NOAA Photo Library

A computer model by Ph.D. astrobiologist Jack O’Malley James, who is at the University of St Andrews, suggests the first changes will take place in only a billion years. He will present his research at the ongoing Royal Astronomical Society national meeting at St. Andrews, Scotland, which is taking place this week.

“Increased evaporation rates and chemical reactions with rainwater will draw more and more carbon dioxide from the Earth’s atmosphere,” the Royal Astronomical Society stated. “The falling levels of CO2 [carbon dioxide] will lead to the disappearance of plants and animals and our home planet will become a world of microbes.”

Earth will then run out of oxygen and begin to dry out as temperatures rise and the oceans evaporate. Around two billion years in the future, there will be no oceans left.

The Sun in H-Alpha with close-up on a rushing prominence on 02-07-2013. Credit and copyright: John Chumack. — The sun, which allows Earth to be life-friendly right now, will warm up the planet and kill off most live forms in the next few billion years. Credit and copyright: John Chumack.

“The far-future Earth will be very hostile to life by this point,” O’Malley James stated. “All living things require liquid water, so any remaining life will be restricted to pockets of liquid water, perhaps at cooler, higher altitudes or in caves or underground.”

Life would disappear almost altogether in about 2.8 billion years.

Thankfully, humans plenty of time to figure out how to get around this problem. In the meantime, we can use the knowledge when seeking life beyond Earth.

Searches these days often focus on finding life like our own, which would leave “fingerprints” behind like oxygen and ozone.

“Life in the Earth’s far future will be very different to this, which means, to detect life like this on other planets we need to search for a whole new set of clues,” O’Malley James stated. “By the point at which all life disappears from the planet [surface], we’re left with a nitrogen:carbon-dioxide atmosphere, with methane being the only sign of active life”.

More information on this research is contained in an April 2013 article in the International Journal of Astrobiology.

Source: Royal Astronomical Society

July 3, 2013December 23, 2015 by Bob King

What You Can See in the Sky While Waiting for Fireworks on The 4th Of July

A thin lunar crescent rises beneath the Pleiades star cluster tomorrow morning at dawn. This map shows the sky facing northeast about 4 a.m. local time. Maps created with Stellarium

The sky can be a showy stage with big-time events like eclipses, meteor showers and the occasional bright comet, but most nights have a quiet beauty that whispers instead of shouts. The contrast between hype and hush is no more apparent than on the 4th of July – American independence day celebration – when we gather at a park or hilltop to watch the fireworks boom and flash across the heavens.

But there are other interesting things — some quiet fireworks — you can see in the sky to see while you are waiting for the holiday fireworks.

You can watch a less flashy but equally satisfying July 4th event as soon as tomorrow morning about the time the first bird lifts its voice at dawn. Look northeast to find a thin crescent moon dangling below the Seven Sisters star cluster. Also called the Pleiades, the cluster is a highlight of the winter evening sky. Though it seems out of place now at the height of summer, the Sisters remind us that nothing stands still. With the solstice behind us, winter’s already buckling his boots.

As you relax before the fireworks begin, look for two bright stars and two bright planets in the west and southwest skies. You can fit about three fists held at arm's length between Saturn and Arcturus. — As you relax before the fireworks begin, look for two bright stars and two bright planets in the west and southwest skies. You can fit about three fists held at arm’s length between Saturn and Arcturus.

While you’re waiting for the show to begin tomorrow night, take a look around the twilight sky and see how many celestial luminaries you can spot. If you’ve got kids in tow, share the view with them, too.

The brightest natural object in the sky will be Venus, glimmering low above the western horizon. Much further up in the southwest, look for a tall, skinny triangle outlined by orangy Arcturus, highest of the three, along with Saturn and Spica.

*Facing east brings the three bright stars of the Summer Triangle in to view.*

Twist around to face east to find another triangle, this one named after the summer season. Halfway up is Vega, the 5th brightest star in the sky, shining white and bright as burning magnesium. Below it you’ll spot the other Summer Triangle members, Altair in Aquila the Eagle and Deneb in Cygnus the Swan better known as the Northern Cross.

These bright stars and two planets coalesced from gas and dust millions to billions of years ago. Much has happened beneath their gaze, from the first stirrings of humankind to the crackle and boom of fireworks on a starry evening.

July 3, 2013December 23, 2015 by Elizabeth Howell

Moon Dust Could ‘Engulf’ Lunar Rovers — Especially During Sunrise and Sunset

Apollo 17 Mission — An Apollo 17 astronaut digs in the lunar regolith to study the mechanical behavior of moon dust. Credit: NASA

That video above is perhaps the ultimate off-roading adventure: taking a rover out for a spin on the moon. Look past the cool factor for a minute, though, and observe the dust falling down around that astronaut.

The crew aboard Apollo 16 (as well as other Apollo missions) had a lot of problems with regolith. It got into everything. It was so abrasive that it wore away some equipment in days. It smelled funny and probably wasn’t all that good to breathe in, either. Many have said that when we return to the moon, dust must be dealt with for long-term survival.

Things could get worse at sunrise and sunset. One new study (not peer-reviewed yet) finds a “serious risk” that rovers “could be engulfed in dust.” That’s because lunar dust appears to have electrostatic properties that, somehow, is triggered by changes in sunlight. (NASA is already doing some serious investigation into this matter using its orbiting missions.)

What the researchers did, in conjunction with ONERA (The French Center of Aerospace Research) was conduct simulations for two types of lunar regions — the terminator (the day/night boundary) and an area experiencing full sunlight.

“Dust particles were introduced into the simulation over a period of time, when both the surface and the rover were in electrical equilibrium,” the Royal Astronomical Society stated.

“In both the test cases, dust particles travel upwards above the height of the rover, but results suggest that they move in different directions. On the day side, the particles are pushed outwards and on the terminator the dust travels upwards and inwards above the rover, regrouping in the vacuum above it. The terminator simulation began with a region void of dust which was later filled by lunar dust particles.”

The bottom line? A lunar rover could accumulate a significant amount of dust on the moon, especially if it’s sitting at or near the terminator. This could be addressed by using dome-shaped rovers that would see the dust fall off, added lead author Farideh Honary, a physicist at the University of Lancaster, in a statement.

The work was presented at the RAS National Astronomy Meeting today (July 3). A paper has been submitted to the Journal for Geophysical Research, so more details should be forthcoming if and when it is published.

Credit: Royal Astronomical Society

July 3, 2013December 23, 2015 by Elizabeth Howell

‘The New Cool’: How These Sharp Space Pictures Were Snapped From A Ground Telescope

A near-infrared view of NGC 4038 (one of the Antenna Galaxies) obtained with the Gemini Observatory's new adaptive optics system. Credit: Image data from Rodrigo Carrasco, GeMS System Verification Team, Gemini Observatory. Color composite image by Travis Rector, University of Alaska Anchorage.

Rise above Earth with a telescope, and one huge obstacle to astronomy is removed: the atmosphere. We love breathing that oxygen-nitrogen mix, but it’s sure not fun to peer through it. Ground-based telescopes have to deal with air turbulence and other side effects of the air we need to breathe.

Enter adaptive optics — laser-based systems that can track the distortions in the air and tell computers in powerful telescopes how to flex their mirrors. That sparkling picture above came due to a new system at the Gemini South telescope in Chile.

It’s one of only a handful pictures released, but astronomers are already rolling out the superlatives.

“GeMS sets the new cool in adaptive optics,” stated Tim Davidge, an astronomer at Canada’s Dominion Astrophysical Observatory.

The planetary nebula NGC 2346. Credit: Gemini Observatory/AURA (Image data from Letizia Stanghellini, National Optical Astronomy Observatory, Tucson, Arizona. Color composite image by Travis Rector, University of Alaska Anchorage.)

“It opens up all sorts of exciting science possibilities for Gemini, while also demonstrating technology that is essential for the next generation of ground-based mega-telescopes. With GeMS we are entering a radically new, and awesome, era for ground-based optical astronomy.”

Other telescopes have adaptive optics, but the Gemini Multi-Conjugate Adaptive Optics System (GEMS) has some changes to what’s already used.

It uses a technique called “multi-conjugate adaptive optics”. This increases the possible size of sky swaths the telescope can image, while also giving a sharp view across the entire field. According to the observatory, the new system makes Gemini’s eight-meter mirror 10 to 20 times more efficient.

The Gemini South telescope during laser operations with GeMS/GSAOI. Credit: Manuel Paredes

The system uses a constellation of five laser guide stars, and has several mirrors that can deform according to measurements obtained by the sodium laser. We have more technical details in this past Universe Today story by Tammy Plotner.

The next step will be seeing what kind of science Gemini can produce from the ground with this laser system. Some possible directions include supernova research, star populations in galaxies outside of the Milky Way, and studying more detail in planetary nebulae — the remnants of low- and medium-mass star.

Check out more photos from Gemini at this link.

Source: Gemini Observatory

July 3, 2013December 23, 2015 by Nancy Atkinson

Astrophoto: Triple Star System Gliese 667 – Home of ‘Goldilocks’ Exoplanets

The nearby triple star system Gliese 667, taken on June 29, 2013. Credit and copyright: Efrain Morales, Jaicoa Observatory, Puerto Rico.

Here is a great new observation of the triple star system Gliese 667 from astrophotographer Efrain Morales of the Jaicoa Observatory in Puerto Rico. Recently, one of the stars, 667 C was found to have perhaps seven planets orbiting it! If all seven planets are confirmed, the system would consist of three habitable-zone super-Earths, two hot planets further in, and two cooler planets further out. Scientists say that the ‘f’ planet is “a prime candidate for habitability.”

Efrain also created an animation of the star system, showing the stars’ movements:

The animation was created using plates from the DSS (Digitized Sky Survey) with the final image in the animation from Efrain’s observations.

Gif animation of The animation of the triple star system Gliese 667, created using plates from the DSS (Digitized Sky Survey) with the final image in the animation from Jaicoa Observatory. Credit and copyright: Efrain Morales. Click for animation.

The system is in the constellation of Scorpius and is just barely visible to the unaided eye at magnitude 5.9 – appearing as a single point of light. The three stars orbit each other in a complicated dance. The two brightest components of this system, Gliese 667 A and Gliese 667 B, are orbiting each other at about 13 times the separation of the Earth from the Sun, while Gliese 667 C is the smallest stellar component of this system, and orbits the other two stars at about 230 AU.

Efrain used a LX200ACF 12 in. OTA, F6.3, CGE mount, ST402xm CCD, Astronomik LRGB filter set.

Thanks to Efrain Morales and the Jaicoa Observatory for providing this latest look at an extremely interesting star system!

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

July 3, 2013December 23, 2015 by Ken Kremer

Curiosity Captures ‘Phobos Rising’ Movie and Sun Setting on Mars

Mars moon Phobos rising in the night time Martian sky shortly after sunset in this image from a movie taken by NASA's Mars rover Curiosity on Sol 317, June 28, 2013. The apparent ring is an imaging artifact The Credit: NASA/JPL-Caltech See the complete ‘Phobos Rising’ movie below

Mars moon Phobos (above, center) rising in the night time Martian sky shortly after sunset in this still image from a movie taken by NASA’s Mars rover Curiosity on Sol 317, June 28, 2013. The apparent ring is an imaging artifact. Credit: NASA/JPL-Caltech
See the complete ‘Phobos Rising’ movie below [/caption]

Every once in a while when the time is just right and no one is looking, Curiosity’s Earthly handlers allow her some night time Martian delights.

In this case a pair of rising and setting celestial events bookend another magnificent week in humankinds exploration of the Red Planet – courtesy of NASA.

This past week NASA’s Curiosity rover captured esthetically stunning imagery of Phobos rising and Our Sun setting on Mars.

Phobos is the larger of Mars pair of tiny moons. The other being Diemos.

On June 28, (Sol 317) Curiosity aimed her navigation camera straight overhead to captured a breathtaking series of 86 images as Phobos was ascending in the alien evening sky shortly after sunset.

NASA combined these raw images taken over about 27 minutes into a short movie clip, sped up from real time.

Video Caption: ‘Phobos Rising’ – This movie clip shows Phobos, the larger of the two moons of Mars, passing overhead, as observed by NASA’s Mars rover Curiosity in a series of images centered straight overhead starting shortly after sunset. Phobos first appears near the lower center of the view and moves toward the top of the view. The images were taken on June 28, 2013. The apparent ring is an imaging artifact. Credit: NASA/JPL-Caltech

The pockmarked and potato shaped moon measures about 26.8 × 22.4 × 18.4 kilometers.

Phobos orbits barely some 6,000 km (3,700 mi) above the Martian surface. One day far in the future, it will crash and burn.

On June 22, Curiosity snapped an evocative series of Martian sunset photos as Sol set behind the eroded rim of Gale Crater – see below.

In the 2030’s, Humans may visit Phobos first before setting foot on the much more technically challenging Red Planet.

In the meantime, enjoy the otherworldly view!

Ken Kremer

Phobos from NASA’s Mars Reconnaissance Orbiter on March 23, 2008. Credit: NASA

July 2, 2013April 26, 2016 by Bob King

Dark Skies – Good For Fireflies And People Alike

Fireflies make green trails of light during a time exposure on a July night. Jupiter is at upper left. Credit: Bob King

Bioluminescent stars flash across the night landscape these July nights. Fireflies or lightning bugs provide a source of wonder for many of us living in the eastern half U.S. and Canada. Did you know dark skies may be as important to them as they are to you and I?

To stoke their yellow-green fires, the bugs – they’re really beetles – cook up light through a series of chemical reactions within their abdomens.

Adult Photurus firefly. Fireflies produce a cool light by combining oxygen in the air with the chemical luciferin. Credit: Bruce Marlin

Oxygen from the air combines with a chemical fittingly named luciferin. Luciferin next hooks up with the energy molecule ATP to form another molecule that when combined with oxygen yields a flash of green, yellow or amber light, depending upon the firefly species.

Fireflies June 30 2013 C — Fireflies compete with the stars from a dark location near Duluth, Minn. two nights ago. Each species has its own specific flash pattern. Credit: Bob King

The males perform the flash-dance moves, wiggling and zigging about to attract the females, who typically remain on the ground hidden among blades of grass. Each species has its own flashing pattern. When a female finds a male’s flashes suitably alluring, she winks a flash back. Back and forth communications soon bring the two together to make more fireflies.

Firefly light emits no heat, making it one of the most efficient light sources known. A standard incandescent light bulb converts electricity into 10% light and the rest as heat; fireflies transform 100% of their chemical energy into light. These insects do not waste photons.

One of my favorite memories from childhood was running around on summer nights collecting fireflies in a glass jar. Credit: Bob King

Every night I’m out under the July stars at least one firefly manages to land within the telescope tube and create a surprise supernova. If I inadvertently switch my LED flashlight on and off at the right rate, more than a few of them will land right on top of the device in a futile attempt to mate.

Urban sprawl and accompanying light pollution is an issue for both astronomers and fireflies. This view shows the light dome from the city of Duluth, Minn. 20 miles north of town. Credit: Bob King

One thing fireflies and skywatchers have in common is love of the night. To appreciate the twinkling heavens, we either escape to the countryside or do our best to contend with the lights in town. Firefly numbers are declining across the U.S. and the world, and though no one’s certain yet why, there’s both anecdotal and scientific evidence suggesting that loss of habitat and light pollution are to blame.

Example showing poorly shielded light fixtures. With nothing to contain or direct the light, it shines where it's not needed - straight up! Credit: Bob King — Example showing poorly shielded light fixtures. With nothing to contain or direct the light, it shines where it’s not needed – straight up! Credit: Bob King

Urban sprawl has comprised the habitats of many wild creatures not just fireflies. Sprawl also brings increased lighting, much of it poorly shielded and on all night. Fireflies avoid heavily lit areas for obvious reasons – light pollution interferes with their ability to see each others’ flashes. Even car headlights can throw them off rhythm. According to a 2008 story in the Boston Globe, controlled experiments have shown that brighter lighting levels cause fireflies to mate less often.

Full cutoff lighting fixtures like these put light where it's needed - on the road - and not out to the sides or up in the sky. Credit: Bob King — Full cutoff lighting fixtures like these put light where it’s needed – on the road – and not out to the sides or up in the sky. Credit: Bob King

We all can help ensure our favorite bioluminescent buddies remain around for a long time. Turning off your own yard light not only helps you to see more stars but makes it easier for fireflies to find their mates. If you absolutely need illumination, consider one of these efficient shielded light fixtures that puts light where you want it while eliminating the glare that frustrates fireflies and stargazers alike. To learn more about good lighting and keeping the sky dark, check out the International Dark Sky Association.

July 2, 2013December 23, 2015 by Nancy Atkinson

Comet ISON: The Timelapse Hubble Movie

A false-color, visible-light image of Comet ISON taken with Hubble's Wide Field Camera 3. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

The Hubble Space Telescope team has released a video of Comet ISON as it is tearing toward its encounter with the Sun, zooming at 77,250 km/h (48,000 miles per hour). The comet’s motion is captured in a timelapse movie, below, made from a sequence of pictures taken May 8, 2013. On that date, the comet was 650 million km (403 million miles) from Earth, between the orbits of Mars and Jupiter.

This sungrazing comet will come closest to the Sun in November 2013, and the debate is on whether it will dazzle the skies and be visible in the daytime or fizzle out due to its close proximity to the Sun.

The movie shows a sequence of Hubble observations taken over a 43-minute span, compressed into five seconds. In that 43 minutes, the comet traveled about 55,000 km (34,000 miles). ISON streaks silently against the background stars.

Source: HubbleSite