Is there an afterlife?

I used to be a Christian and at that time I believed in the after life. As I have learned more about space and the cosmos,I think it's highly unlikely that there is anything after this life. I would dearly like to believe it's possible.
When my sister was dying of cancer ,when she was 46,we talked about this a lot. She always said she would come back as a butterfly.
About 3 or 4 weeks after her death,I went out to put washing on my line and there was a butterfly on the line.
I carried on putting the washing on the line and the butterfly did not move.
I suppose it's fanciful,to think it may have been her,but it cheered me up that day.
That was 22 years ago and I still think of her every day. I still miss her. She was a wonderful person who helped so many people in her counselling work. There were over 400 people at the funeral. Many people had to stand outside the church and listen to the service through a loudspeaker. I often feel her with me.though I know I'm just remembering things she would say or do.
I think ,if it comforts us to think they may hear us,we should talk to them.There's no harm in that.