Earth Archives

July 11, 2013March 16, 2017 by Fraser Cain

What’s the Most Earth-Like Planet In The Solar System?

Life on Earth got you down? Thinking you’d like to pick up and move to another planet? I’ve got bad news for you. Without protection, there’s no place in the entire Solar System that wouldn’t kill you in few seconds.

You’re looking at scorching temperatures, poisonous atmospheres, crushing gravity, bone chilling cold, a complete lack of oxygen, killer radiation, and more.

The entire Solar System is hostile to life as we know it.

If we had to choose from a range of terrible options, what would be the most Earthlike place in the Solar System?

We would want a world that has a similar gravity, similar atmospheric pressure and composition, protection from radiation, and a comfortable temperature. Just like the Earth.

Let’s look at a few candidates:

The Moon looks good. It’s close and… well, it’s close. It’s an airless world, so you’d need a spacesuit. Low gravity is bad news for your bones, which will lose mass and become brittle. Temperatures range from freezing cold to scorching hot, and there’s no atmosphere or significant magnetic field to protect you from the radiation of space.

While we’re suggesting moons, how about Titan, Saturn’s largest Moon?

It’s only 15% of Earth’s gravity, and the temperatures dip down to minus -179 degrees C; cold enough that it rains liquid methane. Even though the atmosphere is unbreathable, the good news is that the pressure is only a little higher than Earth’s. Which means you wouldn’t need a pressurized spacesuit, just a really, really warm coat.

Turning on the Tap - Commissioned artwork - Colonist tapping into a sub-surface aquifer (©Mars Foundation) — Turning on the Tap – Commissioned artwork – Colonist tapping into a sub-surface aquifer (©Mars Foundation)

How about Mars, the target of so many colonization plans and sci fi adventures?

The gravity of Mars is only 38% the gravity of Earth; and we don’t know what effect a long stay in this gravity would have on the human body. The atmosphere is poisonous carbon dioxide, and the pressure is less than 1% of sea level on Earth. So, you’d better pack a spacesuit. The temperatures can rise as high as a comfortable 35 degrees C, but then plunge down to -143 degrees C at the poles. One big problem with Mars is a total lack of magnetosphere. Radiation from space would be a constant hazard for anyone on the surface of the planet.

Perhaps another planet? How about Venus?

On the surface, it’s right out of the running. The temperature is an oven-like 462 degrees C, with a surface pressure 92 times more than Earth. The atmosphere is almost entirely carbon dioxide, with clouds of sulphuric acid. On the plus side, it has gravity roughly similar to Earth, and a thick atmosphere that would protect you from radiation.

Unfortunately, you’d die faster on the surface of Venus than almost anywhere else in the Solar System.

But… there is a place on Venus that’s downright lovely.

Up in the clouds.

Amazingly, if you rise up through the clouds of Venus to an altitude of 50-60 kilometers, the atmospheric pressure and temperature are the same as on Earth. The atmosphere would still be toxic carbon dioxide, but breathable air would be a “lifting gas” on Venus. You could float around the skies of Venus in a balloon made of breathable air. Stand out on the deck of your Venusian sky city in shorts and a T-shirt, soaking up the sunlight in regular Earth gravity.

Sounds idyllic, right?

So, opinions will vary. Some think Mars is the most Earthlike place in the Solar System, but in my opinion, the clouds of Venus are the place to go.

I’ll see you there.

July 8, 2013March 16, 2017 by Fraser Cain

How Will the World End?

There is almost nothing that could completely destroy the earth.

Follow your instincts and ignore anyone raising alarms about its imminent demise.

Oh sure, there’s a pile of events that could make life more difficult, and a laundry list of things that could wipe out all of humanity. Including: asteroid strikes, rising temperatures, or global plagues

In order to actually destroy the Earth, you would need significantly more energy, and there just happens to be enough, a short 150 million kilometers away: the Sun.

The Sun has been in the main sequence of its life for the last 4.5 billion years, converting hydrogen into helium. For stars this massive, that phase lasts for about 10 billion years, meaning we’re only halfway through.

When the Sun does finally run out of hydrogen to burn, it’ll begin fusing helium into carbon, expanding outward in the process. It will become a cooler, larger, red giant star, consuming the orbits of Mercury and Venus.

Scientists are still unsure if the red giant phase of the Sun will consume the Earth. If it does, the Earth’s story ends there. It’ll get caught up inside the Sun, and spiral inward to its demise.

Death by red giant in 5.5 billion years.

If the Sun doesn’t consume the Earth then we’ll have a long, cold future ahead of us. The Sun will shrink down to a white dwarf and begin cooling down to the background temperature of the Universe. The Earth and the rest of the surviving planets will continue orbiting the dying Sun for potentially trillions of years.

Planet orbiting a dead star. Credit: NASA

If we’re exceedingly lucky, the Sun will get too close to another star, and the gravitational interactions will capture Earth in orbit, giving our planet a second chance for life. If not, the Earth will continue following the dying Sun around and around the Milky Way for an incomprehensible amount of time.

At this point, the main risk to the planet is a collision. Or maybe it’ll spiral inward over vast periods of time to be destroyed by the Sun, or collide with another planet. Or perhaps the entire Solar System will slowly make its way into the supermassive black hole at the center of the Milky Way.

One last possibility. Physicists think that protons – the building blocks of atoms – might eventually decay, becoming smaller particles and pure energy. After an undecillion years – a 1 followed by 36 zeros – half of the Earth will have just melted away into energy.

But if protons don’t decay, the Earth could theoretically last forever.

The bottom line, the Earth was built to last.

July 6, 2013December 23, 2015 by Jason Major

New Desktop Image Alert: The Moon Over Earth

If you’re like me, you don’t change your computer’s desktop background nearly often enough… especially not considering all the fantastic space images that get released on an almost daily basis. But this picture, shared a couple of weeks ago by NASA’s Marshall Space Flight Center on their Flickr stream, really should inspire you to fix that. (I know it did for me!)

Captured by an Expedition 28 crew member aboard the International Space Station, this beautiful image shows a crescent-lit Moon seen through the upper layers of Earth’s atmosphere.

As it circles the globe, the ISS travels an equivalent distance to the Moon and back in about a day, making an excellent platform for viewing the Earth and its atmosphere. This photo shows the limb of Earth near the bottom transitioning into the orange-colored troposphere, the lowest and most dense portion of the Earth’s atmosphere. The troposphere ends abruptly at the tropopause, which appears in the image as the sharp boundary between the orange- and blue- colored atmosphere. Silvery-blue noctilucent clouds extend far above the Earth’s troposphere.

Expedition 28 began on May 23, 2011, with a crew consisting of Andrey Borisenko, Ron Garan, Alexander Samokutyaev, Sergei Volkov, Mike Fossum, and Satoshi Furukawa.

Image credit: NASA (Source)

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

June 23, 2013December 23, 2015 by Ken Kremer

NASA’s Daytime Dynamo Experiment Deploys Lithium to Study Global Ionospheric Communications Disruptions

On June 24, 2013 a pair of daytime sounding rockets will launch from NASA Wallops Flight Facility (WFF) and deploy a chemical trail like the one deployed here from a sounding rocket at night. The chemical trail will help researchers track wind movement to determine how it affects the movement of charged particles in the atmosphere. All the colors in the sky shown here, the white and blue streaks, and the larger red blob overhead, are from the chemical trails. Credit: NASA
See Rocket Visibility Maps below[/caption]

NASA WALLOPS, VA – Science and space aficionados are in for rare treat on June 24 when NASA launches a two-rocket salvo from the NASA Wallops Flight Facility, Va. on a mission to study how charged particles in the ionosphere can disrupt communication signals that impact our day to day lives.

It’s a joint project between NASA and the Japanese Space Agency, or Japan Aerospace Exploration Agency, or JAXA.

The suborbital sounding rockets will blast off merely 15 seconds apart from a beach-side launch complex directly on Virginia’s Eastern shore on a science mission named the Daytime Dynamo.

An electric current called the dynamo, illustrated here, sweeps through Earth’s upper atmosphere. A sounding rocket called Dynamo will launch in the summer of 2013 to study the current, which can disrupt Earth’s communication and navigation signals. Credit: USGS — An electric current called the dynamo, illustrated here, sweeps through Earth’s upper atmosphere.A pair of sounding rockets called Dynamo will launch on June 24, to study the current, which can disrupt Earth’s communication and navigation signals. Credit: USGS

Lithium gas will be deployed from one of the rockets to create a chemical trail that can be used to track upper atmospheric winds that drive the dynamo currents.

The goal is to study the global electrical current called the dynamo, which sweeps through the ionosphere, a layer of charged particles that extends from about 30 to 600 miles above Earth.

Why should you care?

Because disruptions in the ionosphere can scramble radio wave signals for communications and navigations transmissions from senders to receivers – and that can impact our every day lives.

The experiment involves launching a duo of suborbital rockets and also dispatching an airplane to collect airborne science measurements.

Mission control and the science team will have their hands full coordinating the near simultaneous liftoffs of two different rockets with two different payloads while watching the weather to make sure its optimal to collect the right kind of data that will answer the research proposal.

A single-stage Black Brant V will launch first. The 35 foot long rocket will carry a 600 pound payload to collect the baseline data to characterize the neutral and charged particles as it swiftly travels through the ionosphere.

Visibility map for Black Brant V rocket launch on June 24 at 9:30 a.m. Credit: NASA Wallops

A two-stage Terrier-Improved Orion blasts off just 15 seconds later. The 33 foot long rocket carries a canister of lithium gas. It will shoot out a long trail of lithium gas that creates a chemical trail that will be tracked to determine how the upper atmospheric wind varies with altitude. These winds are believed to be the drivers of the dynamo currents.

Visibility map for Terrier-Improved Orion rocket launch on June 24 at 9:30 a.m. Credit: NASA Wallops

Both rockets will fly for about five minutes to an altitude of some 100 miles up in the ionosphere.

Since its daytime the lithium trails will be very hard to discern with the naked eye. That’s why NASA is also using a uniquely equipped NASA King Air airplane outfitted with cameras with special new filters optimized to detect the lithium gas and how it is moved by the winds that generate the global electrical current.

The new technology to make the daytime measurements was jointly developed by NASA, JAXA and scientists at Clemson University.

RockOn 2013 University student payload blasts off on June 20,2013 atop a NASA Terrier-Improved Orion suborbital rocket from NASA Wallops at Virginia’s eastern shore. Credit: NASA/Chris Perry

Sounding rockets are better suited to conduct these studies of the ionosphere compared to orbiting satellites which fly to high.

“The manner in which neutral and ionized gases interact is a fundamental part of nature,” said Robert Pfaff, the principle investigator for the Dynamo sounding rocket at NASA’s Goddard Space Flight Center in Greenbelt, Md.

“There could very well be a dynamo on other planets. Jupiter, Saturn, Uranus and Neptune are all huge planets with huge atmospheres and huge magnetic fields. They could be setting up dynamo currents galore.”

The launch window opens at 9:30 a.m. and extends until 11:30 a.m. Back up opportunities are available on June 25 and from June 28 to July 8.

The rockets will be visible to residents in the Wallops region – and also beyond to the US East Coast from parts of North Carolina to New Jersey.

The NASA Wallops Visitor Center will open at 8 a.m. on launch day for viewing the launches.

Live coverage of the June 24 launch is available via NASA Wallops UStream beginning at 8:30 a.m. at: http://www.ustream.tv/channel/nasa-tv-wallops

I will be onsite at Wallops for Universe Today.

And don’t forget to “Send Your Name to Mars” aboard NASA’s MAVEN orbiter- details here. Deadline: July 1, 2013. Launch: Nov. 18, 2013

Ken Kremer

…………….
Learn more about Earth, Mars, Curiosity, Opportunity, MAVEN, LADEE, Sounding rockets and NASA missions at Ken’s upcoming presentation

June 23: “Send your Name to Mars on MAVEN” and “CIBER Astro Sat, LADEE Lunar & Antares Rocket Launches from Virginia”; Rodeway Inn, Chincoteague, VA, 8 PM

Show here are the two types of sounding rockets that will launch on June 24, 2013 from NASA Wallops Island, VA., on the Daytime Dynamo mission. Black Brant V rocket is horizontal. Terrier-Improved Orion rocket is vertical. Credit: Ken Kremer – kenkremer.com

Night time launch of NASA Black Brant XII suborbital rocket at 11:05 p.m. EDT on June 5, 2013 from the NASA Wallops Flight Facility carrying the CIBER astronomy payload. Credit: Ken Kremer- kenkremer.com

June 22, 2013December 23, 2015 by Ken Kremer

Herbal Earth: Spectacular Vegetation Views of Our Home Planet and the Natural World of Living Green Life

Earth’s Vegetation. World map of vegetation created with Suomi NPP data. Credit: NASA/NOAA

Earth’s Vegetation from Suomi NPP satellite. World map of vegetation data collected by the Suomi NPP satellite (National Polar-orbiting Partnership) in a partnership between NASA and the National Oceanic and Atmospheric Administration (NOAA). Credit: NASA/NOAA
Photo and Video Gallery below[/caption]

Herbal Earth: that’s the title of a spectacular collection of vivid new views of the Earth’s vegetation captured over the past year by the Suomi NPP satellite.

NPP is short for National Polar-orbiting Partnership – an Earth science satellite partnership between NASA and the National Oceanic and Atmospheric Administration (NOAA).

Although it’s rather reminiscent of the manmade ‘World at Night’ – its actually the ‘Natural World of Living Green Life.’

The Suomi NPP satellite data were collected with the Visible-Infrared Imager/Radiometer Suite (VIIRS) instrument from April 2012 to April 2013 and used to generate this gallery of images and animations – released by NASA and NOAA on June 19.

Western Hemisphere -Vegetation on Our Planet. The darkest green areas are the lushest in vegetation, while the pale colors are sparse in vegetation cover either due to snow, drought, rock, or urban areas. Suomi NPP Satellite data from April 2012 to April 2013 was used to generate these images. Credit: NASA/NOAA

Suomi NPP was launched on October 28, 2011 by a Delta II rocket and placed into a sun-synchronous orbit 824 km (512 miles) above the Earth. It orbits Earth about 14 times daily.

The VIIRS instrument measures vegetation changes over time by looking at changes in the visible and near-infrared light reflected by vegetation. The 22-band radiometer sensor can detect subtle differences in greenness.

Nile Delta: July 9-15, 2012. Amidst the deserts of Egypt, the Nile River provides life-sustaining water to the region. Also visible are the urbanized areas of northern Egypt. Credit: NOAA/NASA — Nile Delta: July 9-15, 2012. Amidst the deserts of Egypt, the Nile River provides life-sustaining water to the region. Also visible are the urbanized areas of northern Egypt. Credit: NASA/NOAA

The data are incorporated into the Normalized Difference Vegetation Index (NDVI) which represents the photosynthetic potential of vegetation.

The NVDI measures and monitors plant growth, vegetation cover and biomass production from the Suomi NPP satellite information.

The Florida Everglades: March 18-24, 2013. The "river of grass" extending south of Lake Okeechobee shows clear signs of its modified state with areas of dense agriculture, urban sprawl and water conservation areas delineated by a series of waterways that crisscross Southern Florida. Credit: NOAA/NASA — The Florida Everglades: March 18-24, 2013. The “river of grass” extending south of Lake Okeechobee shows clear signs of its modified state with areas of dense agriculture, urban sprawl and water conservation areas delineated by a series of waterways that crisscross Southern Florida. Credit: NASA/NOAA

A quarter of the Earth’s surface is covered by some green vegetation, the remainder is the blue ocean.

Video: Green- Vegetation on Our Planet (Tour of Earth)

And don’t forget to “Send Your Name to Mars” aboard NASA’s MAVEN orbiter- details here. Deadline Very Soon: July 1, 2013. Launch: Nov. 18, 2013

Ken Kremer

…………….
Learn more about Earth, Mars, Curiosity, Opportunity, MAVEN, LADEE and NASA missions at Ken’s upcoming presentation

June 23: “Send your Name to Mars on MAVEN” and “CIBER Astro Sat, LADEE Lunar & Antares Rocket Launches from Virginia”; Rodeway Inn, Chincoteague, VA, 8 PM

Eastern Hemisphere -Vegetation on Our Planet. Credit: NASA/NOAA

June 18, 2013December 23, 2015 by Jason Major

Say Cheese: Cassini to Snap Another “Pale Blue Dot” Picture of Earth

Mosaic of Saturn seen in eclipse in September 2006. Earth is the bright dot just inside the F ring at upper left. (CICLOPS/NASA/JPL-Caltech/SSI)

Citizens of Earth, get ready for your Cassini close-up: once again the spacecraft is preparing to capture images of Saturn positioned between it and the Sun, allowing for incredible views of the ring system and its atmosphere — and also a tiny “pale blue dot” in the distance we call home.

The mosaic above was composed of images captured during such an eclipse event in September 2006, and quickly became an astronomical sensation. It’s not often we get an idea of what we look like from so far away, and seeing our entire world represented as a small speck of light nestled between Saturn’s rings is, to me anyway, both impressive and humbling.

Humbling because of how small we look, but impressive because as a species we have found a way to do it.

And next month, on Friday, July 19 between 21:27 and 21:42 UTC (5:27 – 5:42 p.m. EDT) Cassini will do it again.

“Ever since we caught sight of the Earth among the rings of Saturn in September 2006 in a mosaic that has become one of Cassini’s most beloved images, I have wanted to do it all over again, only better,” said Cassini imaging team leader, Carolyn Porco. “And this time, I wanted to turn the entire event into an opportunity for everyone around the globe, at the same time, to savor the uniqueness of our beautiful blue-ocean planet and the preciousness of the life on it.”

Porco was involved in co-initiating and executing the famous “Pale Blue Dot” image of Earth taken by NASA’s Voyager 1 from beyond the orbit of Neptune in 1990.

“It will be a day for all the world to celebrate,” she said.

The intent for the upcoming mosaic is to capture the whole scene, Earth and Saturn’s rings from one end to the other, in Cassini’s red, green and blue filters that can be composited to form a natural color view of what our eyes might see at Saturn. Earth and the Moon will also be imaged with a high resolution camera — something not yet done by Cassini.

We can all consider ourselves pretty lucky, too… this is the first time in history that we humans will know in advance that our picture is going to be taken from nearly a billion miles away.

“While Earth will be only about a pixel in size from Cassini’s vantage point 898 million miles [1.44 billion kilometers] away, the Cassini team is looking forward to giving the world a chance to see what their home looks like from Saturn,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory. “With this advance notice, we hope you’ll join us in waving at Saturn from Earth, so we can commemorate this special opportunity.”

So on July 19, remember to look up and wave… Cassini will be watching!

Read more on the CICLOPS news release here and on the NASA/JPL Cassini mission site here.

“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… There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”

– Carl Sagan

June 13, 2013December 23, 2015 by Jason Major

Navy Researchers Put Dark Lightning to the SWORD

Dark lightning occurs within thunderstorms and flings gamma rays and antimatter into space. (Science@NASA video)

Discovered “by accident” by NASA’s Fermi Gamma-ray Space Telescope in 2010, dark lightning is a surprisingly powerful — yet invisible — by-product of thunderstorms in Earth’s atmosphere. Like regular lightning, dark lightning is the result of a natural process of charged particles within storm clouds trying to cancel out opposing charges. Unlike normal lightning, though, dark lightning is invisible to our eyes and doesn’t radiate heat or light — instead, it releases bursts of gamma radiation.

What’s more, these gamma-ray outbursts originate at relatively low altitudes well within the storm clouds themselves. This means that airplane pilots and passengers flying through thunderstorms may be getting exposed to gamma rays from dark lightning, which are energetic enough to pass through the hull of an aircraft… as well as anything or anyone inside it. To find out how such exposure to dark lightning could affect air travelers, the U.S. Naval Research Laboratory (NRL) is conducting computer modeling tests using their SoftWare for the Optimization of Radiation Detectors — SWORD, for short.

Terrestrial Gamma-ray Flashes (TGFs) are extremely intense, sub-millisecond bursts of gamma rays and particle beams of matter and anti-matter. First identified in 1994, they are associated with strong thunderstorms and lightning, although scientists do not fully understand the details of the relationship to lightning. The latest theoretical models of TGFs suggest that the particle accelerator that creates the gamma rays is located deep within the atmosphere, at altitudes between six and ten miles, inside thunderclouds and within reach of civilian and military aircraft.

These models also suggest that the particle beams are intense enough to distort and collapse the electric field within thunderstorms and may, therefore, play an important role in regulating the production of visible lightning. Unlike visible lightning, TGF beams are sufficiently broad — perhaps about half a mile wide at the top of the thunderstorm — that they do not create a hot plasma channel and optical flash; hence the name, “dark lightning.”

A team of NRL Space Science Division researchers, led by Dr. J. Eric Grove of the High Energy Space Environment (HESE) Branch, is studying the radiation environment in the vicinity of thunderstorms and dark lightning flashes. Using the Calorimeter built by NRL on NASA’s Fermi Gamma-ray Space Telescope they are measuring the energy content of dark lightning and, for the first time, using gamma rays to geolocate the flashes.

As a next step, Dr. Chul Gwon of the HESE Branch is using NRL’s SoftWare for the Optimization of Radiation Detectors (SWORD) to create the first-ever simulations of a dark lightning flash striking a Boeing 737. He can calculate the radiation dosage to the passengers and crew from these Monte Carlo simulations. Previous estimates have indicated it could be as high as the equivalent of hundreds of chest X-rays, depending on the intensity of the flash and the distance to the source.

Simulation of a Boeing 737 struck by dark lightning. Green tracks show the paths of gamma rays from the dark flash as they enter the aircraft from below. (Credit: U.S. Naval Research Laboratory) — Simulation of a Boeing 737 struck by dark lightning. Green tracks show the paths of gamma rays from the dark flash as they enter the aircraft from below.
(Credit: U.S. Naval Research Laboratory)

SWORD simulations allow researchers to study in detail the effects of variation in intensity, spectrum, and geometry of the flash. Dr. Grover’s team is now assembling detectors that will be flown on balloons and specialized aircraft into thunderstorms to measure the gamma ray flux in situ. The first balloon flights are scheduled to take place this summer.

Source: NRL News

June 10, 2013December 23, 2015 by Jason Major

An Early Start for Noctilucent Clouds

Noctilucent clouds photographed over Killygordon, Ireland on the morning of June 10. (© Brendan Alexander/Donegal Skies. All rights reserved.)

The season for noctilucent “night-shining” clouds is arriving in the northern hemisphere, when wispy, glowing tendrils of high-altitude ice crystals may be seen around the upper latitudes, shining long after the Sun has set. Found about 83 km (51 miles) up, noctilucent clouds (also called polar mesospheric clouds) are the highest cloud formations in the atmosphere. They’ve been associated with rocket launches and space shuttle re-entries and are now thought to also be associated with meteor activity… and for some reason, this year they showed up a week early.

Noctilucent clouds (NLCs) form between 76 to 85 kilometers (47 to 53 miles) above Earth’s surface when there is just enough water vapor to freeze into ice crystals. The icy clouds are illuminated by the Sun when it is just below the horizon, after darkness has fallen, giving them their night-shining properties. This year NASA’s AIM spacecraft, which is orbiting Earth on a mission to study high-altitude ice, started seeing noctilucent clouds on May 13th.

AIM map of noctilucent clouds over the north pole on June 8 (Credit: LASP/University of Colorado) — AIM map of noctilucent clouds over the north pole on June 8
(Credit: LASP/University of Colorado)

“The 2013 season is remarkable because it started in the northern hemisphere a week earlier than any other season that AIM has observed,” reports Cora Randall of the Laboratory for Atmospheric and Space Physics at the University of Colorado. “This is quite possibly earlier than ever before.”

The early start is extra-puzzling because of the solar cycle. Researchers have long known that NLCs tend to peak during solar minimum and bottom-out during solar maximum — a fairly strong anti-correlation. “If anything, we would have expected a later start this year because the solar cycle is near its maximum,” Randall says. “So much for expectations.”

Read more on the NASA AIM page here, and watch the Science@NASA video below for the full story. (Also, check out some very nice NLC photos taken last week in the UK by Stuart Atkinson at Cumbrian Sky.)

Source: NASA