Mike Brown's Planets

The dwarf planet that gets no respect

2013-04-03T18:01:00.000-07:00

Quick: name the three largest known objects in the Kuiper belt. If you’ve been paying close attention you will instantly get Eris and Pluto, and, if pressed, you will admit that no one knows which one is bigger. And the third? An unscientific poll of people who should know the answer (my daughter, my wife, my nephew) reveals that not a single one does. The answer, of course, is Makemake (you

Comets!

2013-03-12T21:56:00.005-07:00

Sometimes I like to write about things in the sky that I've been studying. Sometimes I like to write about scientific discoveries in the outer solar system. Sometimes I even write about wild speculations I have about the solar system. But, every once in a while, I get to just sit back and watch the sky go by. I love comets. When I first started graduate school to get my Ph.D. in astronomy, I

Sea salt (part 3)

2013-03-05T11:09:00.000-08:00

[You should probably start with Part 1] The first thing that you notice when you look at a spectrum of Europa -- from the Earth, from a spacecraft, it doesn’t really matter – is the ice. Ice is everywhere. The spectrum of ice is a very distinctive looking thing, with a quickly recognizable pattern of regions where the sunlight reflects strongly from the surface and regions where there is

Sea Salt (part 2)

2013-03-04T21:36:00.000-08:00

[don’t miss part 1] One of the biggest problems with trying to figure out what is on the surface of Europa was that the spectrograph on the Galileo spacecraft didn’t have a very fine view of the reflected light coming off the surface. The analogy I used in Part 1 was that Galileo was looking at fingerprints where you could only discern the rough pattern and not the individual ridges. You

Sea Salt (part 1)

2013-03-01T05:17:00.000-08:00

Ever wonder what it would taste like if you could lick the icy surface of Jupiter’s Europa? The answer may be that it would taste a lot like that last mouthful of water that you accidentally drank when you were swimming at the beach on your last vacation. Just don’t take too long of a taste. At nearly 300 degrees (F) below zero your tongue will stick fast. The composition of the surface of

There is a Season 5

2013-02-26T17:25:00.000-08:00

Some years back, when I first started writing this blog, I went strong for a year, and then felt a need for a rest. I was writing a book, doing science, raising an infant, all things that took time. So I declared that that was the end of Season 1. After a hiatus I was back. As I remember it, Season 2 was written mostly on weekend afternoons during the times that Lilah napped. But naps don’t

And the answer is....

2011-10-26T22:12:00.000-07:00

Almost a year ago, Eris – the, uh, most massive known dwarf planet -- passed directly in front of an otherwise anonymous star, momentarily causing the star to disappear, as seen from the earth. By carefully measuring the length of time that the star disappeared, astronomers made a very precise measurement of the size of Eris. I care about the size of Eris for many different reasons, but the most

This post might not be wrong

2011-09-10T15:08:00.000-07:00

I have a new scientific paper coming out in the Astrophysical Journal that I am quite proud of having written. Even better, there is a chance that it might not even be wrong. Back in something like seventh grade, I learned how science works. Scientists formulate a hypothesis and then they do experiments, and if enough experiments support the hypothesis, eventually the hypothesis becomes a

The death of the 10th planet

2011-08-24T07:17:00.000-07:00

A remembrance of 5 years ago, today, excerpted from How I Killed Pluto and Why It Had It Coming As an astronomer, I have long had a professional aversion to waking up before dawn, preferring instead to see sunrises not as an early morning treat, but as the signal that the end of a long night of work has come, and it is finally time for overdue sleep. But in the pre-dawn of August 25th, 2005, I

Free the dwarf planets!

2011-08-23T11:05:00.000-07:00

Most people will probably think of tomorrow as the 5 year anniversary of the demotion of former-planet Pluto. That seems fair; the Pluto demotion got all of the news, caused all of the fights, and promoted all of the discussion. But now that tempers have cooled and the world has come to terms with a new more scientific eight-planet solar system, it is time to remember the other important thing

The Redemption of Snow White (Part 3 of 3)

2011-08-20T16:06:00.000-07:00

(don't forget to read Part 1 and Part 2) Snow White’s chance for redemption finally came last year. I got an email from Adam Burgasser, an astronomer at UC San Diego, best known for his studies of brown dwarfs in the local universe (less well known, but perhaps more relevant in this case, is that I was his Ph.D. advisor a decade ago). Adam had just moved from MIT where he had helped design a

The redemption of Snow White (Part 2)

2011-08-11T16:21:00.000-07:00

(read Part 1) One of the nicest things about science is that, usually, when you’re wrong you’re just wrong. There is no use sitting around arguing about it or trying to persuade someone to change his mind, you’re just plain wrong and the universe has explained it to you. Game over. Thanks for playing. Try again later. Next? Only there really was no “next.” Red? For the most part, colors of

The redemption of Snow White (Part 1)

2011-08-09T11:55:00.000-07:00

Nearly four years ago, during the Ph.D. thesis research of my former graduate student Meg Schwamb, we discovered a distant bright Kuiper belt object. Our hope had been that something so distant would be like Sedna – far away, but part of an even more distant population. But it wasn’t. The object was more like Eris – far away, but on its way back in. The object got an official license plate

The seven planets

2010-12-10T12:59:00.000-08:00

[another guest post, this time at boingboing.net ] Back in the good old days everyone knew how many planets there were, then scientists came along and screwed everything up. How could something that was always a planet suddenly not be one? It made no sense. Chaos ensued, people protested, and scientists were thrown in prison. I'm not making up that prison part, either. It was dangerous

Mars attacks

2010-12-07T08:56:00.000-08:00

One of the fun things about having a book coming out [TODAY, IN FACT] is that you get invited to do guest posts here and there around the web. You can, for example, watch for me from now until the solstice over at BoingBoing. One of the most fun so far was a chance to write at Babel Clash, about my take on life on other planets. Here is what I had to say: I grew up in a universe teeming with

There's something out there -- part 3

2010-11-29T15:05:00.000-08:00

In part 1 of this story I told about the discovery of Sedna, the first – and still only – body found far beyond the edge of the Kuiper belt. Part 2 described some of our early theories on how Sedna had gotten there and what it was telling us about the early history of the solar system. Here I’ll begin talking about the most recent searches for more things like Sedna and how we’re doing so far.

How big is Pluto, anyway?

2010-11-22T20:19:00.000-08:00

These days, a question like that is easy to answer: type it in to Google, click on the Wikipeadia entry, and read the answer: 2306 +/- 20 km. The +/- (to be read “plus or minus”) is important here: every measurement has limitations and an often critical part of science is correctly quantifying those limit. The correct interpretation of 2306 +/- 20 km is that 2306 km is the most likely value,

Brian Marsden, gatekeeper of the solar system

2010-11-18T15:23:00.000-08:00

Brian Marsden, long time director of the International Astronomical Union Minor Planet Center died today. While it is easy to say “he was the nicest guy…” in this case it was simply true. Everyone who came across him has stories about Brian. My book, coming out in out a few more weeks has a few too. Just last week I autographed a copy for Brian and bookmarked the spots where he appeared. I say

So is Pluto a planet after all?

2010-11-16T01:19:00.000-08:00

The news last week that Eris might actually be a tiny bit smaller than Pluto led to the inevitable question: doesn’t this mean that Pluto should be a planet, after all? [update: the final analysis suggests that to the best of our ability to measure Pluto and Eris are the same size. No way to know which is bigger or smaller.] The simple obvious answer to this question is no. Pluto was not demoted

Dwarf planets are crazy

2010-11-12T02:29:00.000-08:00

[yet another Eridian digression in lieu of continuing the Sedna story. Sorry! Plus this one is written while staying up all night and trying to run a telescope at the same time. Not the best for coherent writing or fixing typos, but I am losing sleep pondering the strange results from last week’s Eris occultation. And I have not been getting enough sleep to be able to afford the loss.] I’m in

The shadowy hand of Eris

2010-11-07T10:04:00.000-08:00

[sorry: a brief interruption in the ongoing Sedna story for some late breaking news] Eris, the goddess of discord and strife and the most massive dwarf planet, is up to her usual tricks. On Friday night Eris was predicted to pass directly in front of a relatively faint star in the constellation of Cetus. You might think that this sort of thing happens all of the time, but you’d be wrong. Eris is

There's something out there -- part 2

2010-10-28T09:11:00.000-07:00

The view from Sedna (Be sure to read part 1) Seven years ago, the moment I first calculated the odd orbit of Sedna and realized it never came anywhere close to any of the planets, it instantly became clear that we astronomers had been missing something all along. Either something large once passed through the outer parts of our solar system and is now long gone, or something large still

There is something out there -- part 1

2010-10-20T15:13:00.000-07:00

Is it real, or is it cat hair? Seven years ago this week I was preparing one of my favorite lectures for The Formation and Evolution of Planetary Systems, a class I frequently teach at Caltech. “Preparing” is probably the wrong word here, because this lecture, called The Edge of the Solar System, was one I could give even if instantly wakened from a cold deep sleep and immediately put on

Heading South, Looking Up

2010-10-12T13:05:00.000-07:00

For most of the past decade the last thing I would do before going to bed was to step out on to my back patio and stare up at the sky for a few minutes, checking for clouds. If the skies were clear I always slept better. In the morning, I would hop out of bed and do the same thing, to see if any unexpected weather front had passed or cirrus had snuck in while I had been sleeping. If all was

Season 4: The Sabbatical Years

2010-10-06T15:15:00.000-07:00

Mike Brown’s Planets is back. After a long break at the conclusion of Season 3 (I define these Seasons after the fact: if I haven’t written anything in a while I declare it to have been because, clearly. it is the end of the season), the writing will now resume. This season is destined to be the most exciting of all for the simple fact that it also coincides with my current sabbatical, which