Every now and then in life, you come across somebody who changes you.

Five years ago next month, a woman stopped by my blog and left a comment. I clicked back. Her post, that day, happened to be about sitting up rocking her baby through the night.

I’d been sleep-deprived for nearly a year, then: I was frayed and tired, and frequently overwhelmed. Yet here was a woman who wrote a post about sitting up all night with a newborn, a newborn she’d spent months in pain and on bedrest to birth, and those facts were all mere sidenotes.

The post began “Psst…over here. In the half-light of morning. I have something to show you. Someone to show you. Someone wonderful.”

It closed, simply, with”Because I am his mother. And he is my last child.”

Sometimes, a few words can alter your perspective entirely. Hers struck me, and humbled me. There was nothing sanctimonious or saccharine in them, just gratitude and an endurance and appreciation that I am still, five years later, trying to emulate.

This was the first thing Whymommy taught me.

Her name, though I wouldn’t know it for almost a year, was Susan Niebur. A NASA scientist and mother to two tiny boys, she blogged as “Whymommy”: why is the sky blue, Mommy? Why is the rain cold, Mommy? She knew the real answers, Susan did. We became friends.

And then, four months later, she was diagnosed with cancer. Inflammatory breast cancer, a particularly rare and deadly cancer that tends to strike younger women and presents mostly with skin changes – rash, redness, dimpling – on the breast, not with a lump.

She started chemo. She had a double mastectomy. Then another cancer. Lymph side effects. Recurrence.

She lived through hell and she wrote through it, honestly and in detail. But without lamentations.

All through it, Susan’s tone reminded me of that first post: genuine, enduring, appreciative. And all through it, she taught. She used her platform to educate, and to encourage. She altered – and opened – my perspective a hundred times.

She taught me that what matters for cancer patients is research: time, science, hope.  She taught me that cancer awareness needs to translate into action. She taught me that the stars – and the planets and the music of the spheres – are poetry, as well as science, and can be fascinating to even the smallest of kids. She taught me that every day is worth welcoming. And she taught me, again and again, as she had that first time, that the way you choose to look at a situation has an impact on how you experience it: even when it’s grim. Especially when it’s grim.

Susan stared grim down, unflinchingly. And then found beauty where she could, in the gifts of the moment. I have never had a better teacher.

I got to meet her in person, last April. We had one afternoon, running in the rain, gazing at the wonders at the Library of Congress. She bought me my first – okay, only, ever – hoagie. We talked. We laughed.  She was one of the most present people I’ve ever had the privilege of being with.

My friend Susan Niebur died last Monday. She wasn’t yet forty. Her boys – those boys she prized and loved above all else, those boys she endured so much to be here for, as long as she could – are only seven and five.

It is an incredibly sad story. That isn’t why I tell it.

I tell it because, sometimes, just a few words change lives. Susan believed – and stated openly, in our conversation last spring and in the mantra posted on her blog – that all that survives us is what we put into the world: our words and publications, and our love for other people.

She gave me, through her writing and our years of correspondence and friendship, a view of life that I’d never had access to before. She made me think about my parenting – and my time – as more precious than I’d realized. I was lucky enough to have the chance to thank her for these gifts. But to really honour them, and her, I need to share them, put them back out into the world.

Maybe one of you needs a new way to look at the stars.

Maybe one of you needs to taste the wonder of motherhood again, for a minute, rather than the exhaustion.

Maybe one of you needs to remind someone you love to go get a rash or a skin dimple checked out, now.

Maybe one of you just needs to know that even someone struggling and dying believed, with all her wise heart, that the world is a good and worthwhile place.

Maybe one of you needs to be inspired.

(I’ve had the good fortune of being inspired by Susan for almost five years now. It occurred to me this week how profound her impact’s been on how I see my life, and I felt her absence like a hole.

Then I found her Pinterest account. I don’t use Pinterest (yet); I hadn’t seen, til now, what she’d spent hours pinning. Or her commentary. It felt like finding her all over again.)

And so I share Susan, and her wisdom and her words and her life, lived by example. As her husband wrote in the final post on her blog, Toddler Planet, last Monday, “She is survived by her family, friends, achievements, and the indelible marks she made on people around the world.  In lieu of flowers, please consider furthering Susan’s legacy through a contribution to the Inflammatory Breast Cancer Research Foundation.  Or please choose to make a difference somewhere, anywhere, to anyone.”

Words to live by. Now go, do just that.