“Pluto was part of their mental landscape, the one they had constructed to organize their thinking about the solar system and their own place within it. Pluto seemed like the edge of existence. Ripping Pluto out of that landscape caused what felt like an inconceivably empty hole.” -Mike Brown
We had an awfully busy week here on Starts With A Bang, with a number of fun and challenging posts:
- Can two planets share the same orbit? (for Ask Ethan),
- Year in Space vs. Space views from Hubble calendars,
- Ceres’ permanent shadows may house relics from the infant solar system (for Mostly Mute Monday),
- The smallest galaxies in the Universe have the most dark matter,
- More than half of Kepler’s exoplanets are false positives,
- Surprise: the third most common element in the Universe isn’t what you think,
- and Highest resolution images of Pluto reveal the frozen Universe.
For those of you who may not be aware, we’ve started doing monthly podcasts as well, and the second one just went live earlier this week! You can check them all out at SoundCloud, but I’ve embedded the latest one below, so you can listen right here.
Now, join me as we take a dive into our Comments of the Week!
From James Briggs on UFOs: “We all know the picture is real.”
The great thing about photo editing tools is that you can magnify detail that isn’t visible in the original image. Here’s what I did by throwing the original image into a very, very basic image editor (preview or GIMP will work) and just changing the saturation settings.
Lo and behold, the rest of the ISS! Or, as you might conclude, a much, much larger UFO than you ever thought possible.
I’ll leave the interpretation up to you.
From Michael Fisher on Dark Matter hairs: “Layman question. I’m wondering why Gary Prézeau’s paper deals only with compact, planetary masses in his calculations – the centre of Sol is given [via a Google search I did] as having a density of 160 g/cm^3 whereas that of Earth’s inner core is 12 g/cm^3 & that of Jupiter is 25 g/cm^3”
First off, it isn’t the density at the center of the planet that matters so much. Any spherical or spheroidal mass of sufficient magnitude will create this density enhancement along hair-like lines.
The hair that the Earth produces is less enhanced than the hair that Jupiter produces by a factor of 10, but the Sun is further enhanced by more than another factor of 10! The reason it wasn’t highlighted in Prézeau’s paper is that the entire hair is contained within the photosphere of the Sun, from root-to-tip! Going in to detect dark matter is not very productive when the melting point of every material known is less than the Sun’s surface temperature. Oh well.
From Rishi Mishra on Einstein’s relativity and the solar system: “Here is something more on this
Thank you for the opportunity you just gave me to remind people of the cardinal rule of this blog: you are not free to come here and promote your own, alternative theory of physics. You didn’t do exactly that — you just wrote way outside your area of expertise and put together a page full of misunderstandings — but it’s a good reminder.
You’re always welcome here, by the way, and to learn about what we actually know and how we actually know it. I promise I won’t lead you astray, and if I ever do post something incorrect, I’ll correct it.
From Carl on what to be thankful for: “I am thankful for the glorious cosmos, our intricate world, the interlinked biosphere, and the people that walk in shoes different from mine. It took 14 billion years to get here, and we’ve only just begun.”
I agree with all of this. Wherever it is our Universe came from, including the laws that govern it, the particles that exist in it, and the unique way it unfolded to bring about the reality we perceive and our fleeting existence, it’s worth being thankful for all of it.
I don’t know all the answers — I venture that no one, living or dead, does or ever will — but I’m thankful for the time I have as myself in this Universe. Thanks for sharing a little bit of the journey with me.
From Julian Frost on multiple planets sharing the same orbits: “Thank you Ethan. That was really fascinating.”
You know, Julian (and everyone), one of my favorite parts of the Ask Ethan series — and one of the reasons I’ve continued it, uninterrupted, for years now — is that the really provocative questions are the ones that draw upon knowledge from a variety of sub-disciplines in physics and astronomy. It’s incredibly enjoyable for me to get to put them together in comprehensive, in-depth, informative ways that can resonate with non-experts and experts alike.
I very much appreciate knowing that I’ve done a good enough job that you feel informed and fascinated. Don’t forget, everyone, that your questions and suggestions for the rest of the year’s Ask Ethan columns can net you a free Year In Space calendar. Let’s see your best ones!
From Chris Mannering on the CMB and its unexplained anisotropies: “Look at the way the CMB anisotropy – which exhibits cosmological alignments with the ecliptic – in a steadily stronger form, the odds of fluke chance now being on the order of millions to one. Look at how that is hushed up by spoken or unspoken agreement, present company very much included.”
Does it exhibit a cosmological alignment with the ecliptic? Yes, it does.
But is the odds of a fluke chance on the order of millions to one? Not even close. Most analyses give the alignment (or the axis of evil) a fluke chance on the order of a few hundred or a few thousand to one, which is a far cry from the 5-sigma gold standard (and is more like 3.something-sigma) cosmology requires.But let me ask you this: if it did turn out that there were a CMB alignment with the ecliptic, which of these two options would you turn to as the more likely explanation?
1.) The ecliptic itself, containing lots of zodiacal dust, emits foregrounds or otherwise interacts with/absorbs/shifts the CMB radiation to cause this effect.
2.) There is a massive preferred cosmic reference frame, centered on Earth, and in particular on the alignment of our Solar System’s planets with our Sun.
Among scientists, there is no one who takes the second hypothesis seriously. But it sounds like you do. If you do, I would ask you to examine why you think possibility #2 would be the default, and not #1. Assuming, that is, this effect turns out to be robust, and not merely a semi-unlikely by-product of cosmic variance.
From Ron on the Forbes site: “I view your blog on my iPad. [The] link to the Forbes site never gets past the welcome to Forbes page.”
Quite surprisingly, I have an iPad. I never, ever use it, for anything. Anyone who has an iPad and likes it have advice for Ron? I’m at a loss here.
From Denier on dark matter in tiny, tiny galaxies: “Do we see the effect of these dark matter clumps on the outer rim stars of the host galaxy?”
Although these dark matter clumps in the tiniest galaxies — the ones like Segue 1 — are found within the expected halos of other galaxies (like the Milky Way), we have to do the calculation and find out what the expected dark matter density is in that region of space, and compare it to what the density we reconstruct is. In all known cases, the mean dark matter density is many orders of magnitude below what the stars require, necessitating an additional dark matter halo centered on those stars comprising ~100% of the dark matter. (Where ~100% means 95%+, which is indistinguishable from 100% at the precisions/uncertainties we can measure.)
It’s worth noting that one must do the calculation to know for sure.
And finally, from Wow on the latest Kepler results and what they mean for hot exoplanets: “Well, everywhere I’ve ever looked or heard about the formation of stars has ALWAYS said that the normal is multiple star systems, binary and up.
Even for the lay public, that’s been the norm. So I don’t know how this makes our star less unusual being a singleton when finding out that many “large jupiter” planets are liable to be low mass stars.”
This is correct. Which is to say, our star isn’t all that unusual, or isn’t any more unusual than we’d previously thought. Yes, most star systems out there are binaries/trinaries, but a significant minority (between 10-50% by all accounts) are singleton stars, like us. Nothing’s changed there.
What has changed, though, is the amount of “super-Jupiters” we thought existed. Of course, they were the first exoplanets discovered, because they’re the easiest type to detect. But now it turns out that many of them — more than half — may turn out to not be planets after all. It’s always been a grey area as to where the line between “big Jupiter” and “brown dwarf” lies, as there isn’t a hard line of where fusion occurs. True stars, though; that’s a surprise!
This does have strong implications for what the population of super-Jupiters might be overall throughout the Universe, and makes many of us wonder how many more systems might be binaries after all, and how much more abundant low-mass M-dwarfs might actually be.
Thanks for a great week, everyone, and can’t wait to see what the next one brings.
Oh! And whether you’re going to buy my book or not, I do encourage everyone to download the first chapter for free and enjoy it. Free knowledge, illustrated, and researched and written by me. What more could you ask for?