Universe Today

May 8, 2008December 29, 2015 by Fraser Cain

Carnival of Space #53

This week, the Carnival of Space is hosted by the Space Cynics. A big thanks to them for stepping in at the last minute to host this week’s edition.

Click here to read the Carnival of Space #53

And if you’re interested in looking back, here’s an archive to all the past carnivals of space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let me know if you can be a host, and I’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

May 8, 2008December 24, 2015 by Nancy Atkinson

How Far is Mercury from Earth?

Although Galileo wasn’t able to see the phases of Mercury (like the phases of Venus and the Moon) with his first crude telescope, the astronomers that carried on his discoveries did. This was powerful evidence that both Mercury and Earth are orbiting the Sun.

You can also check out these amazing books for more information about the planet Mercury.

Since Mercury orbits the Sun, and it follows a very elliptical path on its journey around the Sun, our two planets can vary their distance significantly.

When Mercury is at its closest point to Earth, astronomers call this opposition (from the point of view of Mercury). This would happen when Mercury was at its furthest from the Sun, and Earth is at its closest. When this happens, Mercury and Earth would be separated by only 77 million km (48 million miles).

Their maximum distance occur when Earth is at its furthest point from the Sun, and Mercury is at its maximum on the other side of the Sun. The three objects then line up perfectly. At this point, Mercury and Earth can be 222 million km (138 million miles) apart.

Distancia desde la Tierra a Mercurio

May 8, 2008August 9, 2016 by Jerry Coffey

How Far is Venus from Earth?

The are varying numbers for the Venus distance from Earth. Each number depends on the relative position of each planet in its elliptical orbit. The point when the planets are at their closest approach to each other is called opposition. The distance between the planets can even vary at different oppositions. The closest possible opposition distance between Earth and Venus is 38 million kilometers. This is the closest that any planet comes to Earth.

The farthest that Venus ever gets from Earth is 261 million km. The means that the Venus distance from Earth can vary by an incredible 223 million km. While that seems like an amazing distance, it is nothing compared to the numbers attributed to other planets. Try to imagine how far it is between Earth and Neptune. Here is a link that tells you how to figure those distances out.

The relative proximity of Venus helps to explain why it is the second brightest object in the night sky. The planet has an apparent magnitude of about -4.9 at its brightest. It can also completely disappear from the night sky when it is at its most distant, because the Sun is between it and the Earth. The planet’s apparent magnitude is also helped by the reflectivity of the sulfuric acid clouds that dominate its atmosphere. The clouds reflect a great deal of visible light, increasing the planet’s albedo and making it more readily seen.

Venus will periodically pass across the face of the sun. This is called a transit. These transits of Venus occur in pairs with more than a century separating each pair. Since the advent of the telescope, transits have been observed in 1631, 1639; 1761, 1769; and 1874, 1882. the most recent occurred on June 8, 2004. The second in this pair will occur on June 6, 2012, so mark your calenders and prepare your telescopes. The planet can also be seen to go through phases much like the Moon when you observe it through powerful binoculars or small telescopes.

Venus is always brighter than any star. It is at its brightest when the Venus distance from Earth is the smallest. The planet can be easy to see when the Sun is low on the horizon, it always lies about 47° from the Sun. The planet orbits faster than the Earth, so overtakes it every 584 days. When this happens Venus is more easily seen in the morning, just after sunrise. Hopefully, you have found quite a bit of useful information here.

We have written many articles about Venus for Universe Today. Here are some interesting facts about Venus, and here’s an article about Venus compared to Earth.

If you’d like more information on Venus, check out Hubblesite’s News Releases about Venus, and here’s a link to NASA’s Solar System Exploration Guide on Venus.

We’ve also recorded an entire episode of Astronomy Cast all about Venus. Listen here, Episode 50: Venus.

References:
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Venus&Display=OverviewLong
http://curious.astro.cornell.edu/question.php?number=564

May 8, 2008December 24, 2015 by Ian O'Neill

Shuttle Launch Controllers Prepared to Press “Self Destruct” Button

Shuttle launch and flight termination panel (NASA)

This is something I can stomach when considering the launch of an unmanned robotic mission into space. It seems obvious that there should be a “flight termination” switch, especially when considering the damage a malfunctioning rocket could do to populated areas. If mission controllers see the rocket veer off course, they can make a quick and decisive action to blow the launch vehicle, and everything on it, out of the sky. But what about Space Shuttle launches? Surely they don’t have a flight termination option too, do they? Well, yes, they do actually. Welcome to the worst job in NASA: launch safety officer.

Every time the Shuttle launches from Cape Canaveral, there is an Air Force officer overseeing events and will probably be the most nervous person in mission control for the first two minutes of the mission. So who is this officer and what does he/she do? The launch safety officer has very big responsibility, not only to the people in mission control, but to the astronauts on board the launching Shuttle and (most critically) the people on the ground in towns and cities under the flight path. Should the Shuttle spin off course, it could crash, killing hundreds or even thousands of civilians. This is why the Shuttle’s two solid rocket boosters are armed with explosives, linked to the controls at the Air Force officer’s fingertips (pictured top). Flipping one switch would arm the explosives; another switch would detonate the spaceship, killing everyone on board.

I’m sure the safety officer will breathe a long sigh of relief as the Shuttle passes the two minute mark without any problems. At this point, the rocket boosters are jettisoned, taking the explosive charges with them. However, this isn’t the end of the worry for the astronauts.

Should something go wrong after booster separation, they will have limited options to prevent crash landing in a populated area. They can either steer the Shuttle into an orbital path (if it is high enough) and fly over the Earth to line themselves up for an emergency landing at California’s Edwards Air Force Base, or they would have to ditch in the Atlantic Ocean. But that’s not the scary part. Before ditching, the astronauts would have to “bail out” at around 20,000 ft (6,000 meters) without the help of ejection seats. They would need to do it the old fashioned way. “After Challenger, we installed parachutes, survival suits and individual rafts, as well as an extendable pole used to clear the escapees from the wing when they exit the hatch [while in flight],” says Bryan O’Connor, a former shuttle commander and NASAâ€™s chief of safety and mission assurance.

You’ll be glad to hear, the upcoming Orion space vehicle will be kitted out with a special rocket-powered escape pod should the worst happen during launch emergencies.

I’m still shocked that the astronauts need an “extendable pole” to clear themselves from the shuttle as they bail out!

Source: Popular Mechanics

May 8, 2008December 24, 2015 by Ian O'Neill

Legendary Astronaut John Glenn Speaks Out On Shuttle Decommissioning

John Glenn watches the NASA archive footage (Larry Downing, Reuters)

On Tuesday, to help out with the 50-year anniversary of the National Aeronautics and Space Administration, clips from 100 hours of restored archive footage of NASA missions were made public. At the screening, John Glenn, America’s first astronaut to orbit the Earth, watched the clips and had time to reminisce over the administration’s “Glory Years”. He also had a very strong message for the policy makers: Extend the Shuttle program and re-commit to a long-term investment in the International Space Station. As a former Marine, Mercury astronaut, pilot and US senator, that’s a hard message to ignore…

In 1962 John Glenn made history. He became NASA’s first astronaut to orbit the Earth, and third US astronaut to travel into space. Starting out as part of the pioneering Mercury Program, Glenn served NASA until 1964 and then entered politics. In 1974 he became a US Senator where he continued till 1999. Add these accolades to his career as a US Marine pilot through World War II and the Korean War in the 1950’s, Glenn has seen more his fair share of action in the air and in space. Not wanting to end his space-faring experiences, at age 77, Glenn was launched on board Space Shuttle Discovery and became the oldest ever person in space in 1998.

On Tuesday, John Glenn attended NASA’s 50th anniversary celebrations on Capitol Hill, Washington D.C. and watched archival footage of the historic achievements of NASA. This included a 1965 clip of astronaut Ed White, taking the first American space walk outside the Gemini IV module. In the clip, White loses a space glove and it is seen floating off into space.

However, under the pride and excitement of the proceeds, there was an air of concern for NASA’s future. Glenn took this opportunity to share his views on the current funding climate for US space missions. In 2015, NASA plans to reduce its commitment to the $100 billion International Space Station, Glenn views this as a lost opportunity.

“The investment we have up there and the potential for learning new things are tremendous at a time when we’re coming under additional global competition.” The International Space Station is “the greatest, most complex laboratory ever put together.” – John Glenn

He was also critical of the decision to retire the Shuttle fleet in 2010, forcing the US to rely more on the Russian space program to supply the station. “The shuttles may be old, but they’re still the most complex vehicle ever put together by people, and they’re still working very well,” he added. Glenn says the benefits of supporting an extension to the Shuttle program will far outweigh the negatives, there is simply no way of knowing where the US will stand politically with Russia in the future, depending on another nation for the lifeline into space could be problematic.

“When we are completely dependent on them for our transportation back and forth, it means we are also subject to the whims they may have politically, as different things happen in the world that have nothing to do with the space program.” – Glenn

Sometimes it takes a NASA legend to highlight the issues facing the future of space flight, let’s just hope someone takes John Glenn’s words on board…

Source: USA Today

May 8, 2008December 24, 2015 by Tammy Plotner

Astronomy Day – May 10, 2008

Are you ready for Astronomy Day? Astronomy Day is a grass roots movement designed to share the joy of astronomy with the general population – “Bringing Astronomy to the People.” During this year’s Astronomy Day on May 10, thousands of people who have never looked through a telescope will have an opportunity to see first hand what has so many amateur and professional astronomers all excited!

Astronomy clubs, science museums, observatories, universities, planetariums, laboratories, libraries, and nature centers host special events and activities to acquaint their population with local astronomical resources and facilities. Many of these events are located at non-astronomical sites; shopping malls, parks, urban centers – truly Bringing Astronomy to the People. If you’re interested in attending such an event, take a look at where current Astronomy Day events being held. This list only encompasses those groups who choose to advertise on the Astronomical League website, so please be sure to check your local news media for other events.

If you, your facility, group or astronomy club is interested in planning astronomy day activities, perhaps you’d like some help! By following the link to the Sky and Telescope Astronomy Day Handbook you can get some great pointers and ideas by downloading the free handbook written by David Levy. While on the page, be sure to visit other great links such as Let’s Go Stargazing and downloadable handouts like the Good Neighbor Outdoor Lighting flyer. The Astronomical League also offers Graphics For Astronomy Day Events and you can even enter your activities in the annual Sky and Telescope Astronomy Award Program!

Need more fun things to do for Astronomy Day that you can reach with just a mouse click? Then know the Abrams Sky Calendar is available for Astronomy Day activities. Anyone celebrating the event is welcome to distribute any number of copies of the Sky Calendar or Sample Sky Map with no restrictions, other than we ask that material not be deleted. How about kid’s activities? Let’s start with coloring pages for Jupiter, Saturn and Mars. You can even make your own Solar System Mobile!

Astronomy Day is an astronomical public relations event that helps highlight ways the general public can get involved with astronomy – or at least get some of their questions about astronomy answered. This important event – Astronomy Day – is co-sponsored by 14 astronomical and astronomy education organizations. They are: The Astronomical League, The Astronomical Society of the Pacific, the Royal Astronomical Society of Canada, the American Astronomical Society, the Astronomical Association of Northern California, the Western Amateur Astronomers, the American Association of Physics Teachers, the Association of Lunar and Planetary Observers, the American Meteor Society, the American Association of Variable Star Observers, the Planetary Society, the National Space Society, the International Planetarium Society, the Association of Astronomy Educators, and the International Astronomical Union.

As the Executive Secretary of the Astronomical League, I’m here to answer any Astronomy Day questions you might have – or point you in the right direction. Spend a few minutes coloring with a child, set up your telescope for a neighbor, take binoculars to work, make copies of the Sky Calendar and Maps and post in your local library. No matter what the size or your event, or level of involvement, it’s all about sharing what you love to do with others. Celebrate Astronomy Day!

May 7, 2008December 24, 2015 by Nancy Atkinson

Volunteers Sweat for NASA

For three weeks, 23 volunteers spent time helping NASA test a new life support system for the spacecraft that will replace the shuttle. Five volunteers at a time would squeeze into a special room the size of a walk-in closet for eight hours. Sweating and heavy breathing was encouraged, as scientists at Johnson Space Center wanted to measure the amount of moisture and carbon dioxide absorbed by a new system designed to control carbon dioxide and humidity inside a crew capsule in order to make air breathable and living space more comfortable. The tests took place from April 14 to May 1 of this year and are some of the first to use human subjects in support of NASA’s Orion crew capsule, Altair lunar lander and lunar rovers.

“We’re moving from paper studies to tests with hardware that will evolve and become part of the spacecraft that will fly back to the moon,” said test volunteer and NASA engineer Evan Thomas at Johnson.

Known as the Carbon-dioxide and Moisture Removal Amine Swing-bed, or CAMRAS, the new system will help sustain life on exploration vehicles and reduce the dependence on resupply from Earth.

“Our goal for CAMRAS is to develop a simple, regenerative, lightweight device that will work for both the Orion crew capsule and the Altair lunar lander,” said lead researcher Jeff Sweterlitsch.

The Exploration Life Support project also is developing technologies that will recover oxygen and water vapor, recycle spacecraft wastewater into drinking water and recover usable resources from wastes.

This series of tests put volunteers inside a test chamber scaled to be the size of the Orion crew capsule, about 570 cubic feet. The volunteers, who were selected and grouped to replicate a typical crew, were asked to sleep, eat and exercise during test sessions that lasted from a few hours to overnight.

“The air smelled a little artificial, like on a plane, and it was a little crowded,” said Aaron Hetherington, one of the volunteers and a director for the test. “But the air was fine; the temperature comfortable. My biggest observation is that it was unremarkable, which is good because that means the hardware was working.”

Two additional phases of testing on CAMRAS are planned.

Video of the tests are available on NASA TV

Original News Source: NASA Press Release

May 7, 2008December 24, 2015 by Nancy Atkinson

The Space Traveler’s Guide to Surviving Without a Spacesuit (Part 1)

In a few decades from now, when we’ve got interplanetary space travel perfected and all of us Average Joes can hop in our own personal spacecraft or grab the local express line of the Milky Way Transport Service, visiting other planets and moons is going to be a blast. Just imagine it: kicking back for a relaxing weekend on Mars, or heading out for a diving expedition on Europa, or possibly week of mountain climbing on Titan. But there are a few safety rules we’ll need to know, especially in the event of a spacesuit failure. Unfortunately, unless someone is able to figure out how to do some serious terraforming, we’ll all be stuck wearing spacesuits in order to survive on the other worlds in our solar system. And just how bad would it be if your spacesuit malfunctioned? Well, let’s just say it wouldn’t be pretty. Here’s a look at some problems you might encounter without an operational spacesuit on other worlds.

We’ll start with Mercury. Lack of air is going to be a serious problem here if your spacesuit quits working. So far, no discernable atmosphere has been detected on Mercury, except for trace amounts of helium, so maybe you could amuse your companions by doing a Munchkin voice for a short while before you passed out. A spacesuit designed for Mercury would have to withstand high temperature fluctuations, as temperatures range from -150 C to 425 C. Without your spacesuit, you’d either freeze or instantly turn into a carbon briquette, depending on which side of the planet you were standing. Moving about on Mercury would be fairly easy, since the gravity is about 1/3 that of Earth, and Mercury has smooth plains, plentiful craters and high cliffs that would be fun to explore. But if you were stuck on Mercury with a malfunctioning spacesuit, it would be a very long bad day, since one day on Mercury is equal to 59 days on Earth.

Venus. Why anyone would want to visit Venus is a mystery. It’s too hot, too cloudy and the atmospheric pressure is downright depressing. A spacesuit designed for Venus would need to be constructed of titanium or some other material that could withstand Venus’ high surface pressure, which is 90 times that of Earth’s. Without a strong spacesuit, you’d be instantly squashed. The Russians tried several times to land a robotic spacecraft on Venus, and most never made it to the surface without being crushed. The Venera 8 lander, however, lasted 50 minutes. So, if your titanium-strength spacesuit was working, and you, too could survive for at least 50 minutes, there are 1600 major volcanoes, lots of mountains, large highland terrains, and vast lava plains to explore. Before landing on Venus, you’d want to do a thorough checkout of your spacesuit’s Primary Life Support Subsystem (PLSS) which contains oxygen tanks, carbon dioxide scrubbers, cooling water, communications, and ventilating fans. You’ll need all of those things to be working at peak efficiency. Venus’ atmosphere is mostly carbon dioxide (96%), with some carbon monoxide and sulfur dioxide thrown in just to keep the riffraff out. Suffice to say, without a spacesuit, you wouldn’t last long and you might not even make it to the surface. And a bad day on Venus would be even worse than on Mercury: it’s about 230 Earth days long.

If you plan just to take a day trip and visit our Moon, you’re probably going to be in pretty good shape, as we’ve had the chance to thoroughly test out spacesuits designed for the lunar surface. Again, you’re going to need your PLSS, since there’s no air on the moon. Just the opposite of Venus, there’s no air pressure on old Luna, so you’ll need your spacesuit to keep your innards inside your body. Surface temperatures can vary dramatically over the course of a day, from 100Â° C at noon to -173Â° C at night, so a malfunctioning spacesuit might cause a predicament. But hopefully there’ll be a moon base just around the corner if you run into any problems.

Let’s head back to the safety of Earth now before we head on out to the rest of our solar system.

Sources: (9) 8 Planets, Windows to the Universe

May 7, 2008December 24, 2015 by Jerry Coffey

Atmosphere of Venus

Earth and Venus share many physical characteristics. Atmosphere is not one of them. The atmosphere of Venus is so harsh that it is the main reason that no one has ever been able to make optical observations of anything other than the planet’s upper atmosphere.

Visualization of the planet is made impossible be the high amounts of sulfuric acid in the atmosphere. Clouds in the upper atmosphere are full of sulfuric acid droplets. Sulfur is highly reflective of visible light, thus preventing observation much deeper than the upper limits of the clouds themselves.

The next challenge that the atmosphere of Venus presents is its composition. It is made up of 96% carbon dioxide. Oxygen can not be detected even as a trace element. At the surface the atmospheric pressure is 92 times that of Earth. If you were able to find a way to survive the intense pressure and had enough oxygen, you would be standing on a surface that is hot enough to melt lead. The temperature across Venus, from pole to pole, is a steady 462°C as a result of the atmosphere’s greenhouse qualities. In the hottest parts of the hottest deserts here on Earth, the temperatures never top 50°C.

The sweltering surface of the planet is covered by volcanoes, impact craters, and old lava flows. There are 1,000 volcanic craters and crater remnants that are over 20 km in diameter. The surface has never been impacted by a small meteorite. The atmosphere burns up anything small. It could take an asteroid in excess of 50 km to survive long enough to hit the surface and then it would have lost close to half of its mass in the atmosphere. The entire planet was resurfaced by volcanic flows between 300 and 500 million years ago.

Several spacecraft have entered the atmosphere of Venus. The first successful probe was the Soviet mission Venera 3, but its instruments failed before entry. Venera 4successfully deployed a number of science experiments. They showed a surface temperature of almost 500°C and an atmosphere that was 90 to 95% carbon dioxide. The atmosphere was much denser than anticipated and its slower descent caused its batteries to run down before reaching the surface. NASA’s Mariner 5 reached the planet one day after Venera 4, but only flew by. The data from the two missions were compared and were an early step in international space exploration cooperation. The Soviet space agency also launched Venera’s 5 and 6. They returned a great deal of information, but were crushed by atmospheric pressure within 20 km of the surface.

There have been over a dozen missions to study the surface and atmosphere of Venus since the Venera program. Currently, the Venus Express mission is in orbit. Bepicolumbo and the Venus in-Situ Explorer are planned. Each mission returns new data, it is hard to imagine what mysteries may be unraveled with a surface explorer.

We have written many articles about Venus for Universe Today. Here are some interesting facts about Venus, and here are some pictures of planet Venus.