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It’s time to chart the future directions of astrobiology research and you can participate. During the month of May, NASA will be hosting a series of on-line hangouts and discussions focusing on broad themes in astrobiology: Planetary Conditions for Life, Prebiotic Evolution, Early Evolution of Life and the Biosphere, Evolution of Advanced Life, and Astrobiology for Solar Systems Exploration. These online conversations will be used as the starting point for a hybrid in-person/virtual meeting to draft an outline of the next Astrobiology Roadmap. To take part in this important conversation and to receive updates, please register at the following website: http://www.astrobiologyfuture.org/. Have your unique voice heard!

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The next full Moon will be on Thursday afternoon, April 25, 2013, passing opposite the Sun in Earth-based longitude at 3:57 pm EDT.  The Moon will appear full for about 3 days around this time, from Wednesday morning (possibly even Tuesday evening) through Saturday morning.  As usual, suitably celebratory celestial costuming could be considered in support of our sated Selene.

As the second full Moon of the Spring season, this is the Flower Moon, as in most areas flowers are abundant this time of year.  Other names include the Corn Planting Moon or the Milk Moon.  This Moon usually falls in May, so it is early this year.

As for other celestial events between now and the full Moon after next:

Sunday and Monday, April 21 and 22, 2013 is the expected peak of the annual Lyrids meteor shower (so called because they appear to radiate out from the constellation Lyra).  This will not be a good year to for viewing the Lyrids, as the light of the nearly-full Moon will make seeing all but the brightest meteors difficult.  If you want to see the Lyrids, the best time to look would be early in the morning on Monday, April 22, 2013, after the Moon sets and before the sky starts to brighten with dawn (between about 4:10 am and 5:20 am EDT for the Washington, DC area).  You would need to be away from city lights with a clear view of the sky, and with no haze or clouds.

On Wednesday, April 24, 2013, the nearly full Moon will appear within about a degree or so of the bright star Spica.  For the Washington DC area, they would have appeared at their closest at about 7 pm EDT, just as the Moon rises, but with the Sun still in the sky the sky will be to bright to see Spica.  As the sky darkens (from sunset at 7:54 pm to the end of civil twilight at 8:22 pm EDT) Spica will become visible, but Spica and the Moon will appear to be drifting apart.  For the Washington, DC area, by the time the Moon reaches its highest point for the night (at 12:30 am EDT on Thursday, April 25, 2013), the Moon will have shifted so that Spica appears about 5 degrees from the Moon.

As mentioned above, the next full Moon is on Thursday afternoon, April 25, 2013.  This will be a partial eclipse of the Moon, but it will not be visible from North America.

On Thursday evening and into Friday morning, April 25 to 26, 2013, the nearly full Moon and the bright planet Saturn will appear within about 4 or 5 degrees of each other.

On Thursday evening and into Friday morning, April 27 to 28, 2013, the waning gibbous Moon will appear about 8 degrees from the bright reddish colored star Antares.

On Friday, April 28, 2013, Saturn will be at opposition, which means opposite the Sun as seen from the Earth.  This is equivalent to a “full Saturn” and will be when Saturn is brightest and closest to the Earth for the year.

Thursday, May 2, 2013, is the last quarter Moon, when the Moon will appear half-full in the morning sky.

Saturday night to Sunday morning, May 4 to 5, 2013, is the peak of the Eta Aquarids Meteor Shower. This meteor shower is caused by dust from Halley’s comet when we pass through the comet’s orbit every year.  This meteor shower is best seen from the southern hemisphere (because the dust is approaching from the south), but if you want to try to see the Eta Aquarids the best time to look is on Sunday morning May 5, 2013 from about 4 am until the sky starts to lighten with dawn.  You will need to find a dark place far from city lights with a clear view of the sky, and no haze or clouds.  The shower runs from about April 19th to May 28th, so it is a fairly broad shower, but the peak is on the morning of the 5th.

Thursday, May 9, 2013, is the new Moon, when the Moon passes between the Earth and the Sun and is not visible from Earth.  The Moon will actually block the Sun as seen from Earth, if you happen to be in the right part of Australia, Papua New Guinea, the Solomon Islands, the Gilbert Islands, or on a ship in the Pacific.  The Moon will be far enough from the Earth that it will not completely block the Sun, so if you are in the right place the bright Sun will appear to form a ring (or annulus) around the dark Moon, making this an annular eclipse.  From North America not even a partial eclipse if visible.

Saturday, May 18, 2013, is the first quarter Moon, when the Moon appears half full in the evening sky.

On Tuesday evening into Wednesday morning , May 21 to 22, 2013, the waxing gibbous Moon will appear within four degrees of the bright star Spica.

The next evening, Wednesday evening into Thursday morning, May 22 to 23, 2013, the nearly full Moon will appear near the nearly full Saturn.

The full Moon after next is on Saturday, May 25, 2013.  The reddish star that will appear about 8 degrees from the full Moon is Antares.

RUMORS. Assuming this is all true, and based on a very first-order look at things, I think they’ve got it. A potentially Earth-like world beyond our solar system. How Earth-like is it? That’ll take a follow-up mission.

Pete Worden: “This is really cool.”

(YES! You bet it is.)

Worden now briefly going over the history of the Kepler mission. Alludes to the struggles Kepler met when it was first starting out.

He’s right… No one thought it would work at first, and now that it’s flying it’s working better than anticipated and might make one of the more historica scientific announcements in my lifetime.

They’re announcing the team now. The inclusion of Lisa Kaltenegger is why I originally suspected this being an announcement of a potentially habitable planet.

2:08-ish – Tweet with hashtag #askNASA If you have questions for the panel….

2:12 – Paul Hertz up now, also giving a shout-out to TESS, which will do things similar to Kepler but for planets around cooler stars but that are more capable of being studied in more detail with a future mission.

(I imagine we’ll talk more about “follow-up” or lack thereof later.)

2:13 – Roger Hunter (Project Manager) up now. Saying we have 2,740 planet candidates (WOW!) and lots of them are Earth or super-Earth sized (2 times Earth’s size or less.) Also going over how Kepler makes its measurements and how it can tell us its orbital properties. Most importantly: the planet’s size and distance from the star.

2:14

Hunter (paraphrased): today we’ll talk about two planetary systems with smaller planets in the habitable zone.

(WOOHOO! For me, this is a HUGE deal. I never believed Kepler 22b will be habitable because it was too big. These won’t be too big.)

2:15

Borucki: Puts up planets we’ll be talking about today, with sized 40% and 60% bigger than Earth.

(I can’t remember the planet names but in my opinion they might as well be called BFD-1 and BFD-2.)

2:16 – Borucki is now going over the concept of the habitable zone, and doing a pretty good job with it. Basically you can’t get too much energy from the star or else you’ll turn your oceans to steam… or you can’t be too far away or they’ll freeze over.

2:17 – Planets are over 1,200 light years away. Showing amazing video now. Three planets in the system. First one is Mars-sized and way too hot for life. Next one is “warm” (cue from me: probably means too hot for life, or may be a “habitable but ONLY IF…” type case). Next one is cooler and could have ice caps.

2:19 – (At this point planetary scientists are banging their heads on their desks at the lightning and oceans and continents being shown but that head-banging misses the point. These planets *COULD* be as imagined. That’s the point.)

2:21 – Borucki going over the importance of size. (This is good, because Kepler 22b (the last “potentially habitable planet” announced by the Kepler team) was probably too big for surface oceans. These are small enough for liquid water oceans.) Based on what I’m seeing so far, at least one of these will be the most habitable planet we know of outside Earth. In my opinion, that even includes Mars, Europa, Enceladus, Venus, etc…

2:22 - Thomas Barclay now talking about a second system, Kepler 69. This star is more Sun-like. Talking about candidate number 172.02 (that’s one that I had internally flagged as being habitable). System includes Kepler-69C, which is 70% bigger than the Earth. That’s pretty big, but still potentially habitable. (I certainly can’t rule it out.)

Barclay (paraphrased) None of these are Earth-sized, but we’re moving in that direction.

2:26:

Lisa Kaltenegger (paraphrased) – Cutoff for “Earth-like” in size is 1.5 Earth radii. We now have planets smaller than this. Take models with a grain of salt…

As someone that runs those models, I’ll agree with that! Hehe. Now she’s showing the habitable zone… that looks like the one made by friend/colleague Ravi Kopparapu! Dr. Kaltenegger now saying that one of the planets is smack in the middle of the habitable zone. (This is critical, because even if some of the measurements are wrong it’ll still be potentially habitable.)

2:28:

Lisa now putting in the grains of salt. For example, no cloud feedbacks in the models. Using that as an argument for why Kepler-62e could be habitable. (I agree, but with STRONG caveats. I’ll get to those later.) Now talking about another that’s a super-Venus. (I’m having trouble keeping up with the names. I’ll have to circle-back later.)

My eyeballing of the figure tells me Kepler-62f is the real star here. Kepler-62e is also interesting, but that’s the one with those caveats.

2:32 – Lisa now waxing poetic about the motivation here. Talking about the diversity of planets and how we might be able to learn something about rocky planets (like Earth) by studying them. And showing a graphical representation (artists rendering, NOT a real image) of what these planets *MIGHT* be like.

Dr. Kaltenegger – “For the first time, we found a system where potentially we could have more than one habitable planet.”

…

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Q&A time.

Q: Is there something special about Sun-like stars?

A (Lisa): What we’re basing out models on is the Earth. If you change the sunlight our models may not account for that. (Not exactly true… but there are other issues.) Other people, some people, want the exact Earth-Sun analog. (This is why Kepler was designed the way it was.) But the big point is the amount of energy you get. Just get closer to the dimmer stars like you would a dimmer fire.

A (Tom): The one planet we know of life on orbits a Sun-like star, so naturally the first planets we should first study in detail would be the ones around Sun-like stars.

A (Bill): IT should also “look like” the Sun from EArth walking around the surface of the planet.

Q: Could they be waterworlds?

A (Lisa): If you take a planet like the Earth with the same water content but bigger… you end up covering the planet with water. The reason is you get more water “faster” than you get more surface area as you go to bigger planets. So that more water will end up covering the Earth. Earth is very dry.

Q: Any reason to think planet inside the habitable zone would have a Venus-like atmosphere instead of Earth-like?

A (Bill): A planet that big you’d expect a lot of CO2. Could make planet even HOTTER.

(So basically, YES.)

Q: Confused… but what about clouds?

A (Lisa): If you make a little more clouds because you have more water vapor in the atmosphere you should be fine.

(They’re hand-waving here a bit, in my opinion.)

A (Lisa): Once you go Venus you don’t go back. It’s a runaway you don’t escape from.

Q: (I missed it, sorry)

A (Bill): You can look at the atmosphere and build an empirical habitable zone. You can also make a model-based zone, similar to what Lisa and others

(COUGH RAVI!!! COUGH) have done.

A (Lisa): Coulds are important here too, but they’re difficult to do.

(You bet they are.)

Q: Is more watery more conducive to early evolution of life? Or more rocky? What kind of life could we expect on them? What kinds of differences?

A (Bill): If we look at our ocean it’s just full of life. We think life started there. !Hints at another press release about getting chemicals needed for life from the subsurface! YOu might have flying fish and birds (??!?) evolved on this ocean planet. (OK you might also have nothing, right?)

Q: Has this been published yet? And can you go over why Kepler-69c might be habitable?

A: Paper was published in the Astrophsical Journal. The planet is in the habitable zone by the metrics for the mission. Probably this planet is “closer” to being Venus than Earth. But slightly farther from its star than Venus is from the Sun, and the star is a little dimmer. So this is “inbetween” the two.

(Basically, in my estimation this planet could be habitable but if AND ONLY IF it has massive cloud or aerosol cover.)

Q: Are there agreements on the habitable zones? Are there different ones? How do you come to agreement on that?

A (Lisa): We do agree. (Mostly.) We figure out how the models work and do our analyses and then come to conclusions. Now talking about how we can have different zones for different approaches (empirical vs. modeling). But either way, Venus is not habitable. There’s an “error bar” in where the planet actually is or how hot the star is. This leads to an “error bar” in how much energy the planet gets. For Kepler-69c you see this error bar and part of the error bar gets into the habitable zone.

(Ahhhh… now I see. If they’re wrong about how much energy this planet gets it *Could* be habitable. That’s actually not as crazy as it sounds. There’s a decent chance that could be the case.)

Q: Where do we go next? TESS? And what’s possible?

A (Bill): What could we do if we had more money? Kepler is the first step. TESS is another step. The next BIG step is something referred to is the Terrestrial Planet Finder. That would look at the atmospheres of the planets and look for water and CO2 and oxygen. Maybe freeons! But that’ll take a much more expensive, extensive mission. Kepler tells us how many planets are out there as a function of size and habitable zone and so on. That will tell us how big of a telescope we’ll need to look at the atmospheres. And then you’d need missions beyond that to confirm life. Missions through our children and grandchildren.

A (Lisa): Habitable zone is defined not where there’s life but where life can be found with a telescope. (This is an OUTSTANDING point by Lisa. This is really what we’re talking about when we talk about the habitable zone.)

Q: Where would Earth and Mars be in our habitable zone?

A (Bill): In our system we wouldn’t have seen anything yet because we haven’t been looking long enough yet.

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OK I have to run. I’ll put up a post later with more fully-formed thoughts.

Checkout the video Seven Wonders of the Microbial World if you want to find out more about the tiny critters that we depend on. Today, we pay homage to our most valued cousins – by talking to them!

Much of recent progress in science, especially in biology and medicine related fields, has been courtesy of bugs like E. coli and T. aquifex. Escherichia coli is found in our guts but is also grown in labs around the world as a means to replicate, isolate and study genes from a variety of organisms. Thermus aquaticus was discovered in a 70°C hot spring at Yellowstone National Park in 1969.  It was the source of the heat-resistant enzyme Taq polymerase, one of the most important enzymes in molecular biology because of its use in the polymerase chain reaction (PCR) which revolutionized genetic studies. Indeed, astrobiologists and researchers studying the origin and evolution of life have also reaped the benefits of Taq and the humble E. coli.

Wouldn’t it be cool to hear what the microbes have to say about their life since joining hands with Homo sapiens in search of life, universe and everything. Well, the team at ChemistryViews Magazine has just interviewed them!

Interview with James T. Aquaticus

Interview with Fridolin E. Coli

It is a hilarious attempt at first contact with the microbial kind – yet a very worthwhile read!

Want more? See Biotoon.com for your microbial edutainment

In Carl Sagan’s words: ” The evolution of life is driven in parts through mutations by the deaths of distant stars. We are, in a very deep sense tied to the cosmos.”

Life has evolved over the past ~ 3 billion years in presence of this radiation, which itself has varied considerably during the period. As demonstrated by the Miller-Urey experiment, lightning plays a very important role in the formation of complex organic molecules, which are the building blocks of more complex structures forming life. There is growing evidence of an increase in the lightning rate with increasing flux of charged particles. Is there a connection between this enhanced rate of cosmic rays and the origin of life? Cosmic ray secondaries are also known to damage DNA and cause mutations, leading to cancer and other diseases. It is now possible to compute radiation doses from secondary particles, in particular muons and neutrons. Have the variations in cosmic ray flux affected the evolution of life on earth?

I have recently written a paper about this with Adrian Melott, where we describe the mechanisms of cosmic rays affecting terrestrial life and review the potential implications of the variation of high-energy astrophysical radiation on the history of life on earth. If anyone is interested in reading further, here is a link with more details:

http://www.bmsis.org/publications/cosmic-rays-and-terrestrial-life/

Here is Carl Sagan’s video explaining it: http://youtu.be/MvHHZO2wmmg?t=1m30s

Last week two important events took place. In the Vatican, the College of Cardinals were guided by the Holy Spirit (or so the legend goes) to choose Jorge Mario Bergoglio as the new Pope of the Roman Catholic Church. As the world learned more about Pope Francis (who as it turns out is a chemistry graduate), not far from Rome, in La Thuile in Italy, physicists upped the ante. Guided by results from the Large Hadron Collider, the physicists announced they were now sure that they had found the God particle.

So what? Well, in one meeting men dressed in red gowns chose a new direction for their institution. In the other meeting, men and women, some in suits, others in jeans, proclaimed it was time to move on to the next stage of understanding the universe we live in. As this is a science blog, let’s look at the latter news in more detail.

Last July, CERN scientists announced that, they had found a new elementary particle weighing about 126 times the mass of the proton that was likely the long-sought Higgs boson. You can read more about the discovery in my earlier post. Unsure, what the Higgs boson is? The Higgs boson is what the Higgs field is made up of and it is the Higgs field which imparts mass to the simplest particles (e.g. electrons and quarks) that are the building blocks of all matter (you, me, everything we can touch and see). One analogy is to think about yourself swimming in a pool of water. As you (the particle) swim through the water (the Higgs field) you feel the friction of the water. The friction is analogous to the interaction that gives a particle in the Higgs field its mass. More interaction means implies a heavier particle. The Higgs bosons, which makes up the Higgs field are like the uncountably many water molecules that fill the swimming pool.

Back in 2012, the two experiments, CMS and ATLAS, hadn’t collected enough data to say the particle was, for sure, the Higgs boson. Now, armed with more data from the LHC, they are reasonably certain that what they have found is a Higgs boson. When asked about the importance of the recent announcement, Andre David, a CMS Physicist, said, “We make progress slowly in trying to define things. We need to be very sure of what they are. We went from a Higgs-like object into a Higgs boson… it smells, quacks, walks exactly like a Higgs boson is supposed to.”

Scientists like plots…and they love animated plots! In the video below, notice how as more data is collected, the signal for the detection at ~126 GeV rises above the background signal.

Detecting a Higgs boson is rare, with just one observed for every 1 trillion proton-proton collisions but based on more than twice as much data as before, the results point firmly towards the particle first described in 1964 by Professor Peter Higgs. When a Higgs boson breaks down into lighter particles, two quantum properties of the boson, its spin and parity, affect the angles at which those lighter particles fly. Scientists from the ATLAS and CMS experiments studied decay pattern of the Higgs-like particle and found the Higgs-like boson is behaving the way the simplest type of Standard Model Higgs boson is supposed to behave. This discovery now eliminates some of the other competing theories for the Higgs boson and marks the end of a decades-long search for the particle, and the beginning of a new effort to understand its place in nature. It also paves way for the much anticipated Nobel Prize for Higgs et al. and perhaps the entire CERN team in the near future.

What’s next? While many physicists will continue to study the properties of this Higgs boson, others hope that relatives of the Higgs particle await discovery. One theory, called supersymmetry, calls for five different varieties of Higgs boson, and could help us understand dark matter. But that will have to wait until 2015 when the collider is turned back on and it breaks its old record of colliding protons at an energy of 8 trillion electron volts and collides them at it is full potential of 13 trillion electron volts.

The Higgs boson news last week coincided with not only with the papal appointment but also Einstein’s birthday and Pi Day… is the universe telling us something?

The next full Moon is on Monday, February 25, 2013.  The Moon will be 180 degrees away from the Sun in Earth-based longitude at 3:26 pm EST, and will appear full for about three days around this time, from Saturday night/Sunday morning through Tuesday evening/Wednesday morning.  As the last full Moon of Winter, this Moon is known as the Worm Moon, Sap Moon, Crow Moon, Crust Moon, or Sugar Moon.  According to the Farmer’s Almanac, the native tribes of what is now the northern and eastern U.S. named this the Worm Moon after the earthworm casts that appear as the ground thaws.  The more northern tribes knew this as the Crow Moon, when the cawing of crows signaled the end of Winter.  Other northern names are the Crust Moon, because the snow cover becomes crusted from thawing by day and freezing at night, or the Sap Moon as this is the time for tapping maple trees.  Europeans called this the Lenten Moon, as the next Moon, the first full Moon in Spring, occurs just before Easter.    This is the time of year when (for the northern hemisphere, at least) the evening sky is full of bright stars.  Our Sun is on the inner edge of one of the spiral arms of our galaxy, and as we look up in the early evenings, we are looking away from the center of the galaxy but towards the densely packed stars of this spiral arm.  After sunset this band of bright stars sweeps across our sky from the southeast to the northwest.  The bright planet Jupiter is also appearing in the evening sky, falling within this band of stars.  >From northern latitudes, when the sky has darkened after sunset, look for the three stars of Orion’s belt.  Follow the line of the belt to the upper right to find the Jupiter (and near Jupiter, the bright star Aldebaran).  Follow the line of Orion’s belt about the same distance to the lower left to find the brightest star in the night sky, Sirius.  Jupiter was at its brightest and closest to the Earth for this cycle back in early December 2012, and over the coming months will appear to grow fainter as its distance from the Earth increases.  Taking over for Jupiter, the planet Saturn will appear to increase in brightness as it draws closer to Earth, with Saturn’s closest approach occurring in late April, 2013.  For the Washington, DC area, on the day of the February full Moon, Saturn will rise at around 11 pm EST, by the March full Moon Saturn will be rising at about 10 pm EDT.  As far as we know, no large objects are passing within the distance between the Earth and the Moon between now and the full Moon after next.  On February 18th (just a few hours ago as I am writing this) a 10-to-15 meter diameter object passed by the Earth at about 1.3 lunar distances, traveling at about 17 kilometers per second relative to the Earth.  On March 18th a 15-to-30 meter diameter object will pass about 4.4 lunar distances from the Earth at about 11 kilometers per second.  As a comparison, the object that shattered windows in Russia was about 17 meters in diameter and traveling at about 18 kilometers per second.  While not passing anywhere near the Earth, a comet MIGHT put on a good show in March.  The comet is named Pan-STARRS.  In June 2011 it was discovered by (and named after) the Panoramic Survey Telescope & Rapid Response System, which scans the sky for Earth-approaching objects that might cause us harm.  This comet will remain farther away from the Earth than the distance from the Earth to the Sun.  However, this appears to be the first time this comet has left the Oort cloud beyond Pluto and entered the inner solar system.  It will be passing slightly closer to the Sun than the orbit of Mercury.  As a fresh comet passing close to the Sun, it might produce a spectacular trail of gas and dust.  Since we know almost nothing about this object there is no way to be sure.  After the comet passes its closest to the Sun onMarch 10, 2013, it will move into the northern skies, which could provide those of us in the northern hemisphere a good view of whatever kind of show it puts on.  The best time to look will probably be March 12th or 13th, when the comet is still relatively close to the Sun (which should mean solar heating will be releasing more gas and dust, and this gas and dust will appear brighter in the sky) but far enough from the Sun to be visible after sunset.  If it is really bright, it could be visible for weeks after this.  While it is easy to predict where the comet will be, it is very hard to predict how bright it will appear, so the best thing to do is to check skywatching web sites, pay attention to the news, and go out and look!As to specific celestial events between now and the full Moon after next: * This evening (Monday evening, February 18, 2013), for the Northern hemisphere, the waxing gibbous Moon will appear about 7 degrees to the left side of Jupiter, with the bright star Aldebaran below and about halfway between. As the evening progresses Jupiter and the Moon will appear to drift farther apart, with Jupiter (and Aldebaran) setting Tuesday morning, February 19, 2013, in the west-northwest around 1:45 am EST (for the Washington, DC area), and the Moon setting 35 minutes later.   * On Sunday night and Monday morning, February 24 and 25, 2013 the nearly full Moon will appear about 6 degrees from the bright star Regulus. * As mentioned above, the full Moon will be onMonday, February 25, 2013. * On Thursday evening and Friday morning, February 28 and March 1, 2013, the waning gibbous Moon will appear within about 2 degrees from the bright star Spica.  The will appear at their closest at about 1 am EST on March 1st.   * The next night, Friday evening and Saturday morning, March 1 and 2, 2013, the waning gibbous Moon will appear about 5 degrees from the bright planet Saturn.  They will appear at their closest at about 4 am EST on March 2nd (and this is also about the time the appear highest in the sky, at least for the Washington, DC area).   * In the morning on Monday, March 4, 2013, the last quarter Moon will appear about 6 degrees above the bright star reddish star Antares.  Don’t forget to march forth on March fourth! * On March 5, 2013, the comet Pan-STARRS will pass at its closest to Earth at about 1.10 Astronomical Units (or about 10% farther than the distance from the Earth to the Sun). * On Sunday morning, March 10, 2013, we “spring forward” with the start of Daylight Savings Time.  Don’t forget to set your clocks ahead one hour.  For the Washington, DC area, on Saturday March 9th sunrise will be at 6:28 am EST and sunset at6:09 pm EST, while on Sunday March 10th sunrise will be at 7:27 am EDT and sunset at 7:10 pm EDT.  The shift to Daylight Savings Time moves the time of sunrise, rounded to the nearest minute, to match the the latests sunrises of the year.  In 2013, for the Washington DC area, rounded to the nearest minute, sunrise was or will be at 7:27 am from January 1st to January 10th, on March 10th, and on December 30th and 31st.   * Also on Sunday, March 10, 2013, the comet Pan-STARRS will be at its closest to the Sun, passing about as close to the Sun as the orbit of Mercury.   * Monday afternoon/evening, March 11, 2013, will be the new Moon.   * On Tuesday and Wednesday evenings, March 12 and 13, 2013, in the glow of twilight about 30 minutes after sunset, look to the west, close to the horizon, for the thin crescent Moon and near it the comet Pan-STARRS.  On Tuesday the comet should appear just to the left of the crescent Moon.  On Wednesday the Moon will have shifted higher in the sky, appearing above the comet.  For the Washington DC area, sunset will be about 7:13 pmEDT, civil twilight will end at about 7:40 pm EDT (a good time to look), and the comet will set around8:20 pm EDT.  These may be the best evenings to view this comet but we are not sure.  The comet could break apart when it is close to the Sun and fizzle out after a few days, or it could produce spectacular dust and gas tails, putting on a bright show that gets better as it appears higher in the evening sky after the 13th.     * On Saturday, March 16, 2013, the waxing crescent Moon will appear about 7 degrees from the Pleiades star cluster.   * On Sunday, March 17, 2013 (St. Patrick’s Day), the waxing crescent Moon will appear between the bright planet Jupiter and the bright star Aldebaran.  Jupiter will appear about 2 degrees above and to the right of the Moon, while Aldebaran will appear about 4 degrees to the left of the Moon.   * Tuesday afternoon/evening, March 19, 2013, the waxing Moon will appear half full as it reaches its first quarter.   * Wednesday morning, March 20, 2013, at 7:01 amEDT, is the Spring equinox, the astronomical end of Winter and start of Spring.   * As the sky darkens on Sunday March 24, 2013, the bright star Regulus will appear about 8 degrees above the waxing gibbous Moon.  As the evening wears on they will appear to drift farther apart.   * The full Moon after next is on Wednesday morning, March 27, 2013.