Posted on by Ian O'Neill

First Images of Asteroid 2008 TC3 Impact Aftermath

The long-lasting persistent train after the impact of 2008 TC3 over the Sudanese skies (NASA)

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A month after asteroid 2008 TC3 hit the Earth’s atmosphere, the first ground-based image of the event has surfaced on the Internet. Admittedly, it’s not the fireball everyone has been waiting to see, but it is visual evidence that something hit us above Sudan on October 7th. The image above was taken from a frame of video that was being recorded by Mr. Mohamed Elhassan Abdelatif Mahir in the dawn following the asteroid impact with the atmosphere. The smoky feature is the remnant of the fireball as the 3 meter-wide asteroid blasted through the upper atmosphere, eventually exploding. The long-lasting persistent train is seen hanging in the air, high altitude winds causing it to twist in the morning sunlight.

We may not have a dazzling fireball re-entry video of 2008 TC3, but this striking image provides the first ground-based evidence of the direct hit, and may help refine the search for any meteorites from the disintegrated asteroid…

Although details are sketchy, it would appear that a person on the ground observed the skies of Sudan shortly after 2008 TC3 exploded in the upper atmosphere. It is unclear whether the observer was part of a meteorite-hunting team, or a Sudanese resident videoing the scene, but it is very fortunate he captured this footage. Dr. Muawia H. Shaddad of the University of Karthoum communicated this single frame, and the picture is being showcased as the November 8th NASA Astronomy Picture of the Day.

It is currently the only ground-based evidence that something hit the Earth at the right time and right location as predicted by scientists using the Mount Lemmon telescope in Arizona as part of the NASA-funded Catalina Sky Survey for near-Earth objects. However, as Nancy reported on October 13th, indirect support for an atmospheric fireball came from a webcam on a beach in Egypt. Also, at 02:43 UTC on that Tuesday morning, an infrasound array in Kenya detected an explosion in the atmosphere (with an energy equivalent of 1.1–2.1 kT of TNT). These observations were backed up by the European weather satellite METEOSAT-8, capturing the fireball from orbit. The pilot of a KLM airliner also witnessed a bright flash, 750 miles from the impact location.

This was the first time that an asteroid has been discovered before it hit the Earth, thereby proving an early-warning system for future asteroid impacts is possible. Although there are 5-10 space rock collision events per year, this is the first time we knew something about it before it happened. This is an amazing achievement as 2008 TC3 was only 3 meters in diameter.

To aid the search for any 2008 TC3 debris, SpaceWeather.com is hoping this image of the aftermath of the October 7th impact will jog any potential witness memories of the African skies a month ago:

Readers, were you in Sudan on Oct. 7th? Send your fireball reports and photos to meteor expert Peter Jenniskens of the SETI Institute. Your data could improve the chances of recovering meteorites.

Sources: SpaceWeather.com, Astroengine.com, NASA APOD

Posted on by Nancy Atkinson

In Their Own Words: Apollo Astronauts say “We Went to the Moon”

Happy 40th Anniversary, Apollo 15!
Image from Apollo 15. Credit: NASA

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Someone approached me recently and wanted to ask about how the US faked going to the Moon back in the 1960’s and 70’s. I was so shocked, appalled and dumbfounded, I really didn’t know what to say. I just directed them to Phil Plait’s Moon Hoax Hoax info. Then I wondered, what do the Apollo astronauts say if someone asks them the same question? Now I know. I just finished watching “In the Shadow of the Moon,” a documentary of the Apollo era presented by Ron Howard, directed by David Sington (*correction). It’s a wonderful film with fantastic and rare footage along with interviews of several of the Apollo astronauts. I highly recommend it! And the end, as the credits are rolling, each of the astronauts responds to an unsaid question about the those who think this greatest adventure in human history was a hoax:

Mike Collins: “I don’t know how I would grab someone by the collar who didn’t believe and shake them and somehow change their mind.” And later Collins added, “I don’t know two Americans who could have a fantastic secret without one of them blurting it out to the press. Can you imagine thousands of people being able to keep this secret?”

Charlie Duke: “We’ve been to the moon nine times. If we faked it, why did we fake it nine times?”

Alan Bean: “Some of the tabloids are saying that we did this in a hanger in Arizona. Maybe that would have been a good idea!” (meaning, it would have been a lot safer)

Dave Scott: “Any significant event in history, somebody has had a conspiracy theory one way or the other about it.”

Gene Cernan: “Truth needs no defense. Nobody, nobody can ever take those footsteps that I made on the surface of the moon away from me.”

And Buzz Aldrin said this on a the UK TV show, “Where Are They Now:” “I’m an honest person. If I tell you I was on the moon and you choose not to believe it, forget it.”

The next time someone approaches me, I’ll be better prepared. And I can hardly wait for the Lunar Reconnaissance Orbiter’s launch early next year. LRO will carry a powerful camera into low orbit over the Moon’s surface. While its primary mission is not to photograph old Apollo landing sites, it will probably photograph them, many times, providing the first recognizable images of Apollo relics since 1972.

The spacecraft’s high-resolution camera, the LROC, or Lunar Reconnaissance Orbiter Camera, has a resolution of about half a meter. That means that a half-meter square on the Moon’s surface would fill a single pixel in its digital images.

Apollo moon rovers are about 2 meters wide and 3 meters long. So in the LROC images, those abandoned vehicles will fill about 4 by 6 pixels.

Check out “In the Shadow of the Moon” website.

Posted on by Nancy Atkinson

Astronomers Discover Odd Kuiper Belt Pair

KBO Binary. Credit: Gemini Observatory

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Astronomers have discovered a pair of small Kuiper Belt Objects that are gravitationally bound to each other. This is somewhat unusual in itself. But even though these two objects are gravitationally connected, they have an enormous separation between them, about 125,000 kilometers (one third the distance from the Earth to the Moon). Astronomers say, as a comparison, this is equivalent to a pair of baseballs gravitationally “connected” and orbiting each other at a distance of 200 kilometers!

The extreme binary, 2001 QW322, orbits at 43 astronomical units or about 6.5 billion kilometers from the Sun. The pair was originally discovered in August 2001 with the Canada-France-Hawai‘i Telescope. Since then, (from 2002-2007), the pair has been monitored closely using 8-meter-class telescopes (Gemini North, Gemini South and the European Southern Observatory’s Very Large Telescope) to obtain high precision photometric observations of the faint double system.

In the above images, their separation was 1.8 arcseconds. Their radii are about 50 kilometers.
There are on the order of about a billion additional Kuiper Belt Objects in our solar system with Pluto and Charon being among the largest members of this important group of minor planets. These small icy bodies move in low eccentricity and low inclination orbits beyond Neptune, extending possibly as far as 1,000 times the distance from the Earth to the Sun.

Most Kuiper Belt Objects are single objects. The advent of adaptive optics and various survey techniques has created a surge in the discovery of binaries in the main asteroid and Kuiper belts. Astronomers say 2001 QW322 clearly stands out as the widest orbit, near-equal mass binary of the solar system.

Source: Gemini Observatory

Posted on by Tammy Plotner

Grus

Grus

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The constellation of Grus was originally created by Petrus Plancius from the observations of Dutch sea navigators Pieter Dirkszoon Keyser and Frederick de Houtman when exploring the southern hemisphere. Grus’ stellar patterns became known when it appeared on a celestial globe in 1597 and was considered a constellation when it was added to Johann Bayer’s Uranometria catalog in 1603. It survived the years to become one of the 88 modern constellations recognized by the International Astronomical Union. Grus is located south of the ecliptic plane and covers approximately 366 square degrees of sky. It is bordered by the constellations of Piscis Austrinus, Microscopium, Indus, Tucana, Phoenix and Sculptor. The asterism consists of 7 main stars and there are 28 stars with Bayer/Flamsteed designations. Grus is visible to all observers at latitudes between +34° and ?34° and is best seen at culmination during the month of October.

Until the late 16th century, Grus was considered part of Piscis Austrinus – the “Southern Fish” – since most of its stars weren’t visible to northern latitudes. When exploration began below the equator many wondrous new creatures were discovered. One such bird was the fishing crane – Phoenicopterus – the flamingo. Perhaps this is how the constellation got is name, since Grus is also Dutch for “crane”!

First let’s take a binocular tour of Grus, starting with its brightest star, Alpha, the “a” symbol on our map. Alpha Gruis proper name is Alnair, the Arabic word for “bright one of the tail”. In this case, it was originally the tail of the fish. But besides being a bit “fishy”, Alnair is a hot, blue subgiant giant star about 101 light years away from Earth. Not only is it larger, hotter and brighter than our own Sol, but it a rather fast stellar rotation – making a complete rotation in under a day. Hop on to Beta Gruis, the “B” symbol on our map. Beta Gruis is a rare kind of star – a cooler class M giant star. It is very possible it is in an advanced state of evolution, losing mass and brightening with a dead carbon-oxygen core in preparation for sloughing its outer envelope – ready to become a Cepheid variable!

Now for visual and binocular double star, Delta 1 and Delta 2 Gruis – the “8” symbol in the center of the constellation. While this pair aren’t physically connect to one another, they do make a pleasing sight with their lovely yellow and red contrasting colors. For a true telescopic binary star, hop north to Upsilon. This disparate pair is separated by over a degree of arc and the difference between stellar magnitudes is a great experience.

For the telescope, tackle NGC 7213 (RA 22:09.3 Dec -47:10) about 16′ southeast of Alpha. This 10th magnitude Seyfert galaxy has definitely got some stories to tell. Not only is it a spiral galaxy, but one that has an incredible,giant H-alpha filament erupting from its nucleus. Another great challenge is NGC 7582, 7590 and 7599 (RA 023:19 Dec -42:3). Here is a small galaxy group consisting of three faint spirals in the same field, all tilted close to edge on. While at least an intermediate sized telescope is need to see them, a wide field eyepiece will place all three in the same field of view at around 100x magnification. Before we leave for the night, let’s try NGC 7410 (22:55.0 -39:40). This uniformly illuminated tilted spiral galaxy shows little sign of structure, despite its bright nature.

Sources: Wikipedia, SEDS
Chart courtesy of Your Sky.

Posted on by Nancy Atkinson

NASA News Too Depressing for a Headline

OK, I give up. I’ve sat here for about a half an hour trying to come up with a headline for this news piece. Actually, there are three different news items I’m combining into one article. One is fairly good news, the other two are very depressing.

First the good news: Today, the first major flight hardware of the Ares I-X rocket arrived in Florida to begin preparation for the inaugural test flight of NASA’s next-generation launch system. But amid this tangible event of moving toward the future comes bad financial news about the Constellation program. Congressional investigators have concluded that the Constellation program is likely to cost $7 billion more than budgeted if it is going to be ready to fly by its target date of March 2015. Without extra money, it could be delayed by 18 months or more.

At the same time another report concludes that NASA would need an extra $2 billion a year to keep its shuttle fleet flying beyond 2010, a measure which would shorten the gap where NASA wouldn’t have a human rated vehicle available for access to space. But doing so would hamper plans to convert a launch pad and other facilities for moon missions, likely delaying Constellation even more.

More money for either Constellation or the shuttle program is just not in NASA’s budget, and shifting money around from other programs “would be disastrous,” NASA shuttle program manager John Shannon said. “What we’re trying to do is find a path that continues to keep Americans flying on American vehicles, but does not mortgage the future of manned space flight,” he said. “We really have to step back and think very hard about what we want the future to look like, and make sure that we’re not going to make it something that is not achievable.”

I need ideas for a headline for this article. Readers — comments?

Both Republican presidential candidate John McCain and Democratic presidential candidate Barack Obama have said they would increase NASA’s budget by $2 billion to minimize the gap between shuttle retirement and the first piloted flights of Ares 1 rockets and Orion crew capsules. (This is being written before the election results are in.) But even that won’t be enough to solve all of the problems.

The Congressional Budget Office report listed several of problems facing the Ares I rocket and the Orion capsule, which NASA hopes will return astronauts to the moon by 2020. Among them are difficulties in developing an engine for Ares and a heat shield for Orion. “NASA has identified several problems associated with the Ares I that could delay successful development of the vehicle,” according to the 18-page report. Read the report here.

We’ve discussed all the issues previously on Universe Today, including intense shaking on liftoff, and concerns that Ares could crash into the launch gantry.

NASA officials said they were studying the report. But agency managers insist the program is on track.

At a news conference NASA held last week to counter reports of Constellation’s problems, Steve Cook, Ares project manager said, “The Ares I rocket is a sound design that not only meets the high safety standards required for a manned spacecraft, it is within budget, on schedule, and meets its performance requirements with margin.”

So what’s the real story? I’m not certain anymore. I desperately want to believe that the media (is that me, too?) overblowing the problems and NASA isn’t just looking through rose colored glasses. But the bad news keeps coming from all fronts.

NASA’s options other than the Ares appear limited.

One proposed option would extend the current space shuttle flight schedule through 2012, using the giant external fuel tanks and other hardware NASA has already planned to build. A second option calls for NASA to build more fuel tanks and hardware to keep flying three shuttle missions per year until 2015.

The CBO report also cautioned that the cost of more shuttle flights could only hurt Constellation under NASA’s limited budget.

Even by throwing more money at Constellation, the investigators also don’t think that NASA could speed up Constellation’s development, at least in the near term. They said NASA told them that “additional funding can no longer significantly change” the March 2015 target date of a first launch.

Even so, the Orlando Sentinel reports that NASA is looking at radical changes in the program to see if it can speed up development.

According to former astronaut Eileen Collins, currently a member of the NASA Advisory Council, one option under consideration would eliminate features needed to go to the moon and turn it a simple craft that could ferry crew and cargo to the space station. That would mean further delays for the real reason for Constellation: returning to the moon.

I thought we had some good news about Constellation last week. But this seems depressing. Too depressing for a headline.

Sources: NASA, Orlando Sentinel, Florida Today

Posted on by Nancy Atkinson

Phoenix Lander Weak But Responsive

The view from Phoenix. Credit: NASA/JPL/Caltech/U of AZ

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After re-establishing communications with the Phoenix Mars Lander late last week, engineers have been able to communicate each day with the weakening spacecraft through relays with the Mars orbiters. But each day, Phoenix runs out of power by late afternoon or early evening. It is able to reawaken the next day after its solar arrays catch morning sunlight. Via Twitter, the lander said it is resting a lot, and hoping to get some strength back in order to do some more science. But each day the amount of time the sun is above the horizon at Mars north polar region diminishes. Additionally, dust raised by a storm last week continues to block some of the sunshine.

“This is exactly the scenario we expected for the mission’s final phase, though the dust storm brought it a couple weeks sooner than we had hoped,” said Phoenix Project Manager Barry Goldstein of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We will be trying to gain some additional science during however many days we have left. Any day could be our last.”

Mission controllers at JPL and Lockheed Martin Space Systems are attempting this week to upload commands to be stored in the lander’s flash memory for science activities to be conducted when the lander wakes up each day.

“Weather observations are our top priority now,” said Phoenix Principal Investigator Peter Smith. “If there’s enough energy, we will try to get readings from the conductivity probe that has been inserted into the soil, and possibly some images to assess frost buildup.”

Source: JPL

Posted on by Fraser Cain

Lunar Year

The Moon with Earthshine. Image credit: Ilmari Karonen

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A lunar year or lunar calendar is one that is based on the cycles of the moon phases. The problem with a lunar calendar is that it drifts away from the seasons. Each year, the start and end dates of each month drift by 11 days. In order to stay correct, every lunar calendar has to deal with this drift away from the calendar year.

Let’s examine a year. A lunar month lasts 29.53 days. So after 12 lunar months, you’re about about 354 days. This is short of the 365 days that it takes the Earth to orbit the Sun. This is a problem since after about 3 years, the lunar months are out of cycle with the solar year by about a month. And this problem would just continue.

To make the lunar calendar work in China, farmers would add in a leap month every 3 years. This would mostly get the lunar month to line up with the solar year, but they still drifted apart somewhat. For some calendars used for religious purposes, such as the Islamic Hirji calendar, they never bothered to sync up the calendars and let them drift. It takes 33 years for the cycle of lunar years to get back to the original position.

A lunar calendar was used in England up until Tudor times.

Want more information about the Moon? Here’s NASA’s Lunar and Planetary Science page. And here’s NASA’s Solar System Exploration Guide.

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Posted on by Fraser Cain

Density of the Moon

NASA's image of the Moon

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The density of the Moon is 3.346 g/cm3. The Moon is actually the second densest moon in the Solar System after Io.

Need some comparisons? The density of Earth is 5.52 g/cm3. This makes it the densest planet in the Solar System. The density of Io is 3.53 g/cm3.

Astronomers believe that the Moon formed when a Mars-sized object crashed into the Earth. The resulting debris from the collision collected into orbit around the Earth and became the Moon. The Moon’s relatively low density comes from the fact that it was mostly the Earth’s upper mantle and crust that was thrown up into space, and not very much of its core.

The low density of the Moon means that it has less mass, and less gravity. If you ever get a chance to stand on the Moon, you’ll see that its gravity is only 16.5% the gravity of Earth. In other words, if you weight 100 kg on Earth, you would only weigh 16.5 kg on the Moon.

Want to know the density of other objects in the Solar System? Here’s the density of Jupiter, the density of the Sun, and the density of Saturn (the least dense planet in the Solar System).

Want more information about the Moon? Here’s NASA’s Lunar and Planetary Science page. And here’s NASA’s Solar System Exploration Guide.

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Posted on by Fraser Cain

What is the Moon Made Of?

The composition of the Moon is a bit of a mystery. Although we know a lot about what the surface of the Moon is made of, scientists can only guess at what the internal composition of the Moon is. Here’s what we think the Moon is made of.

Like the Earth, the Moon has layers. The innermost layer is the lunar core. It only accounts for about 20% of the diameter of the Moon. Scientists think that the lunar core is made of metallic iron, with small amounts of sulfur and nickel. Astronomers know that the core of the Moon is probably at least partly molten.

Outside the core is the largest region of the Moon, called the mantle. The lunar mantle extends up to a distance of only 50 km below the surface of the Moon. Scientists believe that the mantle of the Moon is largely composed of the minerals olivine, orthopyroxene and clinopyroxene. It’s also believed to be more iron-rich than the Earth’s mantle.

The outermost layer of the Moon is called the crust, which extends down to a depth of 50 km. This is the layer of the Moon that scientists have gathered the most information about. The crust of the Moon is composed mostly of oxygen, silicon, magnesium, iron, calcium, and aluminum. There are also trace elements like titanium, uranium, thorium, potassium and hydrogen.

Want to compare the Moon to other objects in the Solar System? Here’s what the Earth is made of, and here’s what Mars is made of.

Want more information about the Moon? Here’s NASA’s Lunar and Planetary Science page. And here’s NASA’s Solar System Exploration Guide.

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Posted on by Fraser Cain

Moon Activities for Kids

NASA's image of the Moon

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Want to help your kids learn more about the Moon with some interesting activities? Here are some Moon activities that we can suggest:

  • Learn the phases of the Moon – For this activity, you need a bright light to represent the Sun, and a ball that you can use as the Moon. Have your child sit on a chair away from the light. The child is the Earth. Then orbit the child in a counter-clockwise direction. The child should see the different amounts of illumination on the ball representing the Moon.
  • Organize the phases of the Moon – Draw out all the Moon phases on pieces of paper and mix them all up. Let your children arrange them into the proper order, starting with the new moon going to the full moon, and then back again. You can refer to a calendar of Moon phases if you need to know if they’re right.
  • Make craters – Drop marbles or ball bearings into a material that shows how craters can form. To make your lunar surface, put a layer of a white material, like flour in a pan to a depth of a few cm. Then cover it with a thin layer of something dark, like cocoa powder. When you drop the marbles into the material, it will create very familiar looking craters.
  • Feel your weight on the Moon – Calculate your child’s weight on the Moon by multiplying their current weight by 0.165. For example, if they weigh 30 kg, they would only weigh 5 kg on the Moon. Have them stand on a bathroom scale and then support their weight until the scale shows their moon weight. Now let them walk around the room with you supporting the bulk of their weight. That’s what it would feel like to walk on the Moon.

Want more activities? NASA has a huge list of cool space activities on their website.

We also have instructions on how you can build a model of the Solar System.

Want more information about the Moon? Here’s NASA’s Lunar and Planetary Science page. And here’s NASA’s Solar System Exploration Guide.

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?