Oh, how I wish we had half-star ratings on Goodreads; this was really, for me, a 2.5, but it's definitely not a three, and I wasn't willing to round up. The "it was ok" alt-text on the second star really sums it up, anyway, so there you go. To quote another review of this book, Gravity was definitely a mixed bag. I'm quite fond of it for being a book about a queer girl period, because lordy-loo how sick I am of going searching for queer-themed YA and getting nine books about boys for every one about girls, and to throw in the main character's Jewish identity -- well, I was biased from the start. Unfortunately, Gravity is...dry, in large part, which to some extent works, with Ellie being sort of awkward and socially inept, but I feel like, for the most part, that's not so much an intentional way of building Ellie as a narrator as clumsiness on Lieberman's part.
As others have noted, Lieberman isn't Orthodox, and she may not be queer, either (apparently she's married to a man, though that certainly doesn't rule out her being bi). As others have ALSO noted, there's no real need for the story to be set in 1987 (and indeed, at one point Ellie's mother complains about the rudeness of a woman talking on her cell phone at the Western Wall), which is never a good sign for a non-contemporary story: if the time doesn't serve the characters and the story, they don't need to be there. The glaring anachronism also points to some pretty lackluster editing, which does give me some hope for future works by Lieberman: a decent editor, who can explain to her that you don't need every other word out of a character's mouth to be "um" and to give her a lot of nervous tics by way of showing that she's AWKWARD, DID YOU NOTICE HOW AWKWARD SHE IS (drinking game: drink every time Ellie says "um" or chews on a hangnail), might go a long way towards bringing out the shine.
The which shine is there in Gravity! That's what makes the places where it falls flat so disappointing, really -- there's a truly WONDERFUL book here, but alas, it needed at least one more good, hard edit before it was ready to hit the shelves.